# Probability Random Guesses

If a student randomly guesses, what is the probability that the student will pass the test? A) 0. If you make random guesses on all 4 problems, What is the probability that all 4 of your answers are incorrect?. ) What is the probability that player 1 selects a. The probability distribution for X, probability distribution for the random variable X = the number of days. For a random guess (you have no clue at all), the probability of guessing correct should be 1 4 1 4 because there are four options and only one option is correct. If a student guesses on each question, what is the probability that the student will pass the test? 24) A) 0. Number of random guesses needed to guess a number in a given set [duplicate] Browse other questions tagged probability random or ask your own question. She picks a random answer (guesses) the other 10 answers because she really isn't sure about their answer. probability of the coin landing heads up exactly six times? 4) A six-sided die is rolled six times. Investment Probability. hardest probability ever please help An unprepared student makes random guesses for all of the answers. 8) What is the probability that 6 rolls of a fair die will show exactly three fives? 9) A test consists of 10 true/false questions. CHAPTER 4 THE BINOMIAL AND NORMAL PROBABILITY MODELS TABLE OF CONTENTS Page 1 The Binomial Probability Distribution 112 Conditions for a Binomial Experiment, Bernoulli Trials 112 Mean and Standard Deviation of a Binomial Random Variable 112 Using Excel and Table 1 to Calculate Binomial Probabilities 113 2 The Normal Probability Model 119. probability of getting exactly 4 defects in a batch. In other words, the odds for such a coincidence is about 1 in 10,000 words. A quiz consists of 20 multiple-choice questions, each with 6 possible answers. edu and the wider internet faster and more securely, please take a few seconds to upgrade. Conversely, the probability of getting an answer wrong is 75%. If each question has five possible answers, only one of which is correct, what is the probability that a student who guesses at random on each question will pass the exam? Answer. What is the probability of drawing a face card or a 4? 10) In one town, 51% of all voters are Democrats. A student who forgot to study guesses randomly on every question. 5 students are selected at random to form a committee. An urn contains M white and N black balls. In general, the same is true for the probability. Probability distribution for correct answers based on "realistic" multiple choice tests. If all answers are random guesses, estimate the probability of getting at least 20% correct. Find the indicated probability. In other words, the odds for such a coincidence is about 1 in 10,000 words. 155Test2reviewdy2 5 October 18, 2011 For Problems 19 and 20, assume that voltages in a circuit vary between 5 volts and 11 volts, and voltages are spread evenly over the range of possibilities ﴾Uniform Distribution﴿. The relative frequency is always between 0% (the event never occurs) and 100% (the event. $\endgroup$ – Bob Hanlon Aug 5 at 14:23. This chapter. The number of completely wrong guesses is 200 (5*5*8). So far, we've seen how the laws of probability predict the outcome of large numbers of experiments involving random data, how to calculate the probability of a given experimental result being due to chance, and how one goes about framing a hypothesis, then designing and running a series of experiments to test it. Figure below shows the results of tossing a coin 5000 times twice. Cars Households 0 125 1 428 2 256 3 108 4 83 A) 0. [The normal probability distribution is an example of a continuous probability distribution. Enjoy the videos and music you love, upload original content, and share it all with friends, family, and the world on YouTube. Although equations and formulas may be too advanced for elementary school students, simple probability can help students in making educated guesses and decisions. It is unlikely that Dr. The Kruskal Count is a card trick invented by Martin Kruskal in which a magician “guesses” a card selected by a subject according to a certain counting procedure. The variable x is a random variable because its values depend on chance. For someone who makes random guesses for all of the questions, find the probability of passing if the minimum passing grade is 90%. MULTIPLE CHOICE. Moreover, the change in the index in any given year is not influenced by whether it rose or fell in earlier years. The musician makes 10 correct guesses in exactly 10 trials. 29 RANDOM STOCK PRICES A believer in the "random walk" theory of stock markets thinks that an index of stock prices has probability 0. The actual exam will be much shorter. We calculate p(X= 1) = 11 66 = 1 6: We calculate PfX= 2g= X11 i=2. Find the probability that there is at least one correct answer. The possible values of x are 0, 1, 2, and 3. 24) A test consists of 10 true/false questions. How many three letter words (without meaning) are possible when repetition of letters is not allowed? What is the probability that those words will not start with a vowel. If each question has four choices and you guess on each question, what is the probability of getting exactly 7 questions correct? n = 10 k = 7 n – k = 3 p = 0. A) 364 365 B) 31 365 C) 1 365 D) 12 365. Then, player 1 selects a coin at random from the chosen box and tells player 2 whether the coin is a gold coin or a penny. What is the probability of exactly 5 correct guesses? 8. Find the probability that the new product introduced was by the second group. 11) Find the probability of correctly answering the first 2 questions on a multiple choice test if random guesses are. Let 3 4 be the probability that he knows the answer and 1 4 be the probability that he guesses. Help on Normal Sampling? 1)Use normal approximation to estimate the probability of passing a true/false test of 40 questions if the minimum passing grade is 70% and all responses are random guesses. Statistics and Probability Trivia Questions & Answers : Math This category is for questions and answers related to Statistics and Probability, as asked by users of FunTrivia. The computer will tell you if each guess is too high or too low. with 4 possible answers. Construct a table describing the probability distribution, then find the mean and standard deviation for the random variable x. "Probability matching in choice under uncertainty: Intuition versus deliberation" Probability matching has been characterized as "dumb" (reflecting operations of heuristic judgment) and as "smart" (adaptive in environments in which outcomes may follow patterns). Stripped of the obfuscation, Schroeder says that it is statistically impossible for single-celled life such as bacteria to have formed by a random combination of chemical reactions. 060 21) 22) According to government data, the probability that an adult was never in a museum is 15%. The expected value can really be thought of as the mean of a random variable. use the binomial probability table to find the indicated probability for the number of correct answers. or more will be female. Assume that random guesses are made for 10 multiple choice questions on an ACT test and that there are 5 choices for each question with probability of success 0. Probability distribution for correct answers based on "realistic" multiple choice tests. The total number of possibilities is 324 (6*6*9). • Take an M&M out of a bag and look at the color. Example: Consider jobs arriving at a job shop. One way to think of it, we want to figure out the possibilities that involve out of the five flips, four of them are chosen to be heads, or four of them. ) What is the probability that player 1 selects a. A quick quiz consists of 4 multiple choice problems, each of which has 6 answers, only one of which is correct. Winning a lottery with 1 million contestants. 3 question 4 In answering a question on a multiple choice test, a student either knows the answer or guesses. Work out the likelihood of an event in. TarGuess-I uses PII such as your name and birthday. A) 364 365 B) 31 365 C) 1 365 D) 12 365. Imputing text data using markov random fields. Tom draws two cards. In answering a multiple-choice question, a student either knows the answer or guesses. Random numbers can still be used in selecting data from other probability distributions, by using an inverse transform of the related cumulative distribution function. Grimmett 1/4/10, 17/11/10, 5/7/12. Each student has 4 possible answers of which only one is correct. In a class of 40 students, what is the probability of finding five left-handers? C. 95 if someone has the disease, but the probability is only. Round to three decimal places. fixed Reset Selection Question 7 of 20 1. Studies have shown that short term returns in the stock market are random, although with a positive bias. As in algebra, random variables are represented by letters. Binomial Probability • Frequently used in analyzing and setting up surveys • Our interest is in a binomial random variable X, which is the count of successes in n trials. The probability is 124 out of 324, which can be reduced to 31 out of 81. The probabilities that the first and the second groups will win are 0. Objective: Compute probabilities and quantiles for a binomial random variable representing the number of correct guesses on a multiple-choice test and visualize these quantities using the Binomial Applet. Lecture #5 chapter 5 Discrete Probability Distributions 5-2 Random Variables Def: A random variable, x, represents a numerical value, determined by chance, assigned to an outcome of a probability experiment. What are the chances atleast one 6 or atleast one 5 was observed among the 6 rolls? b. A - 4% B - 20% C - 1% D - 16% E - 5% F - 7% G - 3% H - 21% I - 6% J - 17% Now, I need to randomly generate 3 items from the above list in each draw, according to their assigned probabilities, but lets say if first item is B, the second and third item should not be B. Each student has 4 possible answers of which only one is correct. If a student guesses on each question what is the probability the student will pass the test?. Find the probability that John guesses at most 7 questions correctly. 0 Points If a student randomly guesses at 20 multiple-choice questions. Prove Proposition 4. 3 people) and having them all fall into a particular group (in our case, they are in favor of health care). Use the multiplication rule to find the probability that the first two guesses are wrong and the third and fourth guesses are correct. A party consists of n males and n females. If two voters are randomly selected for a survey, find the probability that they are both Democrats. The following example illustrates many of the above points. On 75% of the questions, Pat thinks she knows the answer; and on the other 25% of the questions, she just guesses at random. assume that random guesses are made for five multiple-choice question on an ACT test, so that there are n=5 trials. 1 Discrete Random Variables1 4. Solution: Let $$X$$ denote the number of questions that the student guesses correctly. Choose from three difficulty levels. The SP800-63 approach is to find the largest value of M such that. 20 use binomial probability Find the probability that the number of x correct is ATLEAST 3. The probability that he gets 5 correct is given by. 1 Answer by Expert Tutors. Number of random guesses needed to guess a number in a given set [duplicate] Browse other questions tagged probability random or ask your own question. 4) remain the same. (i) Draw a tree diagram for Tarek. Question two is true or false and the person is guessing, so the probability he guesses the correct answer is 1/2. Find the probability that the number x of correct answers is no more than two. I'm looking for a slightly better theoretical understanding of "crazy wisdom", as if that's possible. Delete, Predecessor, Successor, Maximum, and Minimum, The basic data structure that we use to represent. What is the probability of guessing any one answer right? Calculate the probability that. For a specific sample size, the width of a 95% confidence interval on µ. Once that is known, probabilities can be computed using the following formula. Find the probability that there is at least one correct answer. By assuming that each of the 63 = 216 possible outcomes is equally. How do you beat, say, 100 random decisions between "PLAYER/DEALER" like they have in Bacarrat or the "PASS/DON'T PASS" from Craps. Rules of Complement As we have seen before, the probability of something certain to occur (occurring 100% of the time) is one. 060 23) The probability that an individual is left-handed is 0. 000064 B) 0. SUGGESTED SYLLABIA variety of. If , , and are independent random variables that are uniformly distributed over , compute the probability that the largest of the three is greater than the sum of the other two. Round your answer to three decimal places. From Sections 3. Winning a lottery with 1 million contestants 6 times in a row. This means that the probability that two random walkers in two dimensions meet is the same as the probability that a single walker in two dimensions ever returns to the starting point. Well, out of our five flips we want to select four of them to be heads, or out of the five-- We're obviously not actively selecting. Calculate the probability of guessing a random number between 1 and 100. A student makes random guesses for 10 true/false questions. Probability that our discrete random variable X is greater than or equal to two, well, that's these three scenarios right over here. A student. - If player 2 guesses correctly, then player 2 keeps the selected coin. 999 Probability of exactly one correct answer: There are ten ways the student can get exactly one correct answer (one for each possible question they could have guessed correctly). Probability of passing a quiz with random guesses. Prove Proposition 4. So probability is all you need, in some sense. P (odd sum is, given 1 number is a 1) = 6/11. If a student randomly guesses, what is the probability that the student will pass the test? A) 0. If two voters are randomly selected for a survey, find the probability that they are both Democrats. 26) Find the probability of answering two true or false questions correctly if random guesses are made. Minesweeper can be played two ways: as a game of logic or as a game of probability. probability of the coin landing heads up exactly six times? 4) A six-sided die is rolled six times. Help on Normal Sampling? 1)Use normal approximation to estimate the probability of passing a true/false test of 40 questions if the minimum passing grade is 70% and all responses are random guesses. A quiz consists of 20 multiple-choice questions, each with 5 possible answers. To control quality, a random sample of 60 completed items is selected each day and inspected. Now we want to convert this to a cumulative probability which should go from zero to one. The probability of an event occurring is somewhere between impossible and certain. b) What is the probability that a random science major is male? 7. Find the probability of passing if the minimum passing grade is 60%. Although equations and formulas may be too advanced for elementary school students, simple probability can help students in making educated guesses and decisions. Then carry out twenty more trials of the simulation using the random number generator on your graphing calculator. 4) remain the same. If a student randomly guesses, what is the probability that the student will pass the test? A) 0. Find the indicated probability. drops and 4 lemon drops. So far, we've seen how the laws of probability predict the outcome of large numbers of experiments involving random data, how to calculate the probability of a given experimental result being due to chance, and how one goes about framing a hypothesis, then designing and running a series of experiments to test it. Tschaepe examines such guesses at greater length with the instance of guessing a number between 1 and 100, for which Tschaepe notes that the guesser "has to look for clues that are specific to what. The probability p = 0:5 means he is not randomly guessing but is making intelligent guesses based on some knowledge (but we assume independence between questions). i I I I i i 414 J. So that means if you give your test to 200 students, and 25 of those 200 students never studied at all and just guess randomly, there is more than a 75% chance that at least one of those random guessers walks away with a B or better. Let $\frac{3}{4}$ be the probability that he knows the answer and $\frac{1}{4}$ be the probability that he guesses. Assume the questions each have five choices for the answer. For someone who makes random guesses for all of the answers, find the probability of passing if the minimum passing grade is 50 %. “Probability matching in choice under uncertainty: Intuition versus deliberation” Probability matching has been characterized as “dumb” (reflecting operations of heuristic judgment) and as “smart” (adaptive in environments in which outcomes may follow patterns). Adding the disadvantage of points lost for wrong answers - say the fair deal : 3 points for a correct answer, -1 for a wrong answer - , reduces your chances to 0. ILLUSIONIST Derren Brown claimed he was able to predict the lottery numbers just by combining the random guesses of a panel of members of the public. Calculate the probability of guessing a random number between 1 and 100. P(X<4)equals=. Question one is true or false and the person is guessing, so the probability he guesses the correct answer is 1/2. Life is unpredictable, and probability is our best mathematical handle on real-world uncertainty. ABX Binomial Probability Table. What is the probability of the student passing the test with at least a 70%? Small companies might be interested in the number of long-distance phone calls their employees make during the peak time of the day. If a student guesses on each question, what is the probability that the student will pass the test? 24) A) 0. Find the probability that there is at least one correct answer. — Michael A Osborne (@maosbot) 28 September 2018 Having seen this debate sporadically erupt over a decade or so has burned the issue of random decision making deep into my psyche, where it has lurked until I recently had reason to think a bit more deeply about the use of random decision making in my own research area: modelling animal behaviour. Are those two events independent? b. Since all the answers are independent (the answer to one question has no bearing on the answers to the others), then this is the case with each question, so the chances of guessing all answers correctly is 1/3 × 1/3 × 1/3 = 1/27. 1) Find the mean of the binomial distribution for which n = 70 and p = 0. Objective: Compute probabilities and quantiles for a binomial random variable representing the number of correct guesses on a multiple-choice test and visualize these quantities using the Binomial Applet. The science of counting is captured by a branch of mathematics called combinatorics. As you can see that one million is $10^6$ you can then see that winning it 5 times in a row would be identical to pick one value out of $10^{6^5} = 10^{30}$ values. There are good guesses and there are bad guesses. Binomial Distribution: Example #1. SOLUTION: an unprepared student makes random guesses for the ten true-false questions on a quiz. Each student has 4 possible answers of which only one is correct. There are 4 possible answers per question. How many three letter words (without meaning) are possible when repetition of letters is not allowed? What is the probability that those words will not start with a vowel. a quick quiz consist of true false question follow by multiple choice with 4 possible answers, I find probabilities of both response correct, a multiple-choice question with 4 possible answers followed by a true/false question. 14046 3) 4) A multiple choice test has 30 questions, and each has four possible answers, of which one is correct. You win if you can guess the number within six tries. What is the probability that Joan guesses the correct answer on exactly four of the five questions? (4 points) 6. The line up contained 5 men. The a priori probability for a random coincidence is, hence, equal to 1/10. guesses are made and each Il) You are dealt two cards successively (without replacement) from a shuffled deck of 52 playing cards. A personal probability. The success of the trick is based on a mathe-matical principle related to coupling models for Markov chains. Assume that random guesses are made for 10 multiple choice questions on an ACT test and that there are 5 choices for each question with probability of success 0. Work out the likelihood of an event in. However, social scientists are also sometimes interested in the joint probability associated with multiple random variables. The line up contained 5 men. Write all the probabilities on your diagram. It has been stated that about 41% of adult workers have a high school diploma but do not pursue any further education. Probability - Random Numbers Given that a lottery has 10 million potential combinations, what are the odds that someone will win with 90% confidence given that 10 million tickets are sold. What is the probability, remember, X is the number of packs of cards Hugo buys. The expected value is what you should anticipate happening in the long run of many trials of a game of chance. EBook Problems Set - Rules for Computing Probabilities Problem 1. The probability distribution for X, probability distribution for the random variable X = the number of days. Assuming that a student who guesses at the answer will be correct with probability $\frac{1}{4}$. Find the probability that there is at least one correct answer. I need to know the probability of any 3-digit number randomly matching with an established 3-digit number outcome. I'll explain: If any number in the random sequence matches any number in the outcome sequence, but NOT in the same placeholder spot, it gets an X score. A quiz consists of 10 multiple-choice questions, each with 4 possible answers. The probability that a household contains three people must be A) 0. Albert randomly guesses. The probability of assigning an instance as true positive by the model will be (x*x) (for true negative it is ((1-x)^2). Random variable: c = the color of the M&M. Recognize the binomial probability distribution and apply it appropriately. To pass the test a student must get 60% or better on the test. Let 2/3 be the probability that the student knows the answer and 1/3 the probability he guesses. Running Supervised Learning ¶. What if we toss a coin two times?. For someone who makes random guesses for all of the answers, find the probability of passing if the minimum passing grade is 40 %. Some problems are easy, some are very hard, but each is interesting in some way. Show that X is a binomial random variable. Generally, for applications where the random numbers are absolutely critical, it's best to find an alternative to the Random object. Each question has four possible choices. Determine if the following situations suggest a random variable with a binomial distribution: The number of questions correct if one randomly guesses on a quiz of 20 multiple choice questions where each question has 4 possible answers; The number of people with blue eyes in a group of 10 people drawn from a room of 30 people without replacement. Tutors, sign in to answer this question. This probability is different because they give us a restriction with the "given that one f the cubes shows a one". An unprepared student makes random guesses for the ten true or false questions on a quiz. The binomial probability formula is used to find probabilities for Bernoulli trials. The probability on a single random draw, from a normal deck of cards, is 1/52. Sort colored shapes into a three circle Venn Diagram. A relative frequency probability based on physical assumptions. $\endgroup$ – Bob Hanlon Aug 5 at 14:23. Having said that picking the same number is probably going to better than just picking random numbers every time purely because the probability of getting large strings of the same number goes down exponentially each time, so the chance of getting say 20 2's in a row is very very rare (but it is expected to happen given enough trials). Problem Description: A multiple choice test has four possible answers to each of 16 questions. The random variable x is the number of houses sold by a realtor in a single month at the Sendsom's Real Estate office. An unprepared student makes random guesses for the ten true-false questions on a quiz. This means that if you ran a probability experiment over and over, keeping track of the results, the expected value is the average of all the values obtained. Find the probability of correctly answering the first 3 questions on a multiple choice test if random guesses are made and each question has 6 possible answers. What is the probability that the student answers. Any physical theory is a kind of guesswork. in from Latest Edition Books as per NCERT (CBSE) Guidelines. Winning a lottery with 1 million contestants. A student takes random guesses at each problem on a 15-problem quiz. Because SPSS will not let you do anything without data just type something into the first blank cell (e. Moved Permanently. Define the random variable: X = _____ c. What is the probability that the student answers exactly. Calculate and interpret expected values. Question three is true or false and the person is guessing, so the probability he guesses the correct answer is 1/2. The addition rule helped us solve problems when we performed one task and wanted to know the probability of two things happening during that task. This lesson deals with the multiplication rule. assume that random guesses are made for five multiple-choice question on an ACT test, so that there are n=5 trials. Presumably you need to stretch 10 calls to rand() into 1,000,000 quality random numbers because rand() is very slow (and hopefully generates very good random data in return). You're using an out-of-date version of Internet Explorer. Many pin verification systems allow only three attempts, so there is 1/3333 chance of someone correctly guessing your pin before the system is blocked. If all answers were guesses, find the probability of getting exactly four correct answers. Albert randomly guesses. Find the probability that the new product introduced was by the second group. If there is no right answer, the probability to randomly choose a right answer is 0%, (since there is none). "Probability matching in choice under uncertainty: Intuition versus deliberation" Probability matching has been characterized as "dumb" (reflecting operations of heuristic judgment) and as "smart" (adaptive in environments in which outcomes may follow patterns). 50 with a standard deviation of 2. 999 Probability of exactly one correct answer: There are ten ways the student can get exactly one correct answer (one for each possible question they could have guessed correctly). Read this as "X is a random variable with a binomial distribution. guesses are made and each Il) You are dealt two cards successively (without replacement) from a shuffled deck of 52 playing cards. 375 4) 5) Find the probability of answering two true or false questions correctly if random guesses are made. Let pbe the probability that he knows the answer and 1 pbe the probability that he guesses. Of the 10 answers she guesses, probability says that she will get 10/5 = 2 correct and 10 - 2 = 8 wrong. 1 Sample space, events, probability • In this chapter, we will study the topic of probability which is used in many different areas including insurance, science, marketing, government and many other areas. Let X = the number of Patti's correct guesses. From this it's clear that A i,j = 0 for all i,j such that i ≥ j (because we always reduce the remaining range by at least 1 with each guess). Use the Central Limit Theorem to find the probability that the mean guess : $will be between 3900 and 4100. Find the probability that the student guesses exactly 14 answers correctly. A relative frequency probability based on physical assumptions. Find the probability of passing if the minimum passing grade is 60%. Find the probability that there is at least one correct answer. The first argument is an example of statistical inference because it is based on probability. Each question has 5 choices. Suppose we have 6 chances to guess a random number between 1 and 100, then it's obvious that the probability of getting the correct answer is$\frac{6}{100}\$. Now we want to convert this to a cumulative probability which should go from zero to one. Arandom variable describes the outcomes of a statistical experiment in words. How do you beat, say, 100 random decisions between "PLAYER/DEALER" like they have in Bacarrat or the "PASS/DON'T PASS" from Craps. Calculate the probability of guessing a random number between 1 and 100. As an example: roll a die twice, find the random variable X that the sum is a prime number. AP Statistics Solutions to Packet 8 X All have the same probability of saying "yes" since they are randomly chosen from the at random, the number of. Winning a lottery with 1 million contestants 5 times in a row. I'm assuming the hacker isn't guessing randomly, but without replacement. If all answers are random guesses, estimate the probability of getting at least 20% correct. Moved Permanently. The probability of selecting the winning Powerball number is 1 42. A Review of Basic Probability: Days 1-2 (or 3) **On your TI-84, choose the APPS menu: Choose “Prob Sim” from the menu: Then press any key. Assuming that all responses are random guesses, find the probability that among 12 test subjects, exactly five answer the question correctly. Each random variable has a probability distribution that gives us information about the likelihood that a specific event happens (like 13 or more correct guesses out of 21) and about what’s expected to happen if the chance behavior is repeated. probability of getting exactly 4 defects in a batch. guesses is or , the probability to guess correctly in any one of those tests remains or. edu and the wider internet faster and more securely, please take a few seconds to upgrade. any numeric random variable b. Make a complete list of the differe answers, and then find the probability for each entry in the list. The probability on a single random draw, from a normal deck of cards, is 1/52. Then X has a binomial probability distribution with n = 25 and 0. a random variable is called a geometric random variable. Each problem is a multiple choice question with 5 possible solutions. Tutors, sign in to answer this question. 006 12) The length of time it takes college students to find a parking spot in the library parking lot follows a normal distribution with a mean of 3. For each question we have 4 choices. Follow the instructions on the calculator to count the number of times a 1 is rolled. To make intelligent guesses What's the weather like tomorrow? What are the chances of a drug working? What kind of customer will buy my product? Should I buy a lottery ticket? Two? Is it a boy or girl? Frequency probability How often a result comes up if an experiment is repeated again and again Bayesian probability. or more will be female. It is unlikely that Dr. There is also a lazy version of this walk. Show that X is a binomial random variable. probability judgments within one individual, but did not ﬁnd evidence of such an effect. Because the student had such a busy schedule, he or she could not study and guesses randomly at each answer. EasyFit allows you to easily calculate probabilities from more than 50 distributions using StatAssist - the built-in distribution viewer and calculator. The line up contained 5 men. find the probablity that there is at least one correct answer. 6) and his probability of failure ( q = 0. For someone who makes random guesses for all of the questions, find the probability of passing if the minimum passing grade is 90%. Discrete Probability Distributions 5-2 Random Variables Def: A random variable, x, represents a numerical value, determined by chance, assigned to an outcome of a probability experiment. Guess definition, to arrive at or commit oneself to an opinion about (something) without having sufficient evidence to support the opinion fully: to guess a person's weight. What is the probability that 7 or. 24) A test consists of 10 true/false questions. This range is determined by the lowest and highest potential values for that variable. the questions? If a student makes random guesses, what is the probability that the student will make exactly 5 questions correct? Answer: 2 1024, (10,5)/1024 0. Recognize the binomial probability distribution and apply it appropriately. Define guesses.