Author:
Christine Farr

1) Suppose that μ = 155 and σ = 20. Find the score 2.2 standard deviations above the mean.2051991901852) Suppose that μ = 155 and σ = 20. Find the score 2.8 standard deviations below the mean.899095993) Two people are selected at random from 6 men and 9 women. The random variable is thenumber of men selected. Give all possible values of the random variable.0,1,2,30,1,20,1,2,3,41,2,34) Identify the random variable as discrete or continuous: the volume of water in LakeMichigan.discretecontinuous 5) Customers at a local were shopping mall were asked to state which of three brands ofcoffee tasted the best. The brands were numbered 1, 2, and 3. The results are summarizedin the table.If the brand number is a random variable, does this define a probability distribution?YesNo6) When a new floral shop opened, a record of the daily number of phone calls was kept.The records showed the following data.Let the number of calls be the random variable X. Use this summary to determine theprobability that the number of phone calls is 4 per day.1/301/151/103/107/157) A U. S. History professor has a test bank of questions for a quiz on the United Statespresidency. The test bank has seven true-false questions, three discussion questions, andten multiple choice questions. The computer randomly selects ten questions. Let therandom variable X be the number of multiple choice questions. List the possible values ofX.X ={1,2, ..., 20}X ={1,2, ...,10}X ={0,1, 2,3, ...,20}X ={0,1, 2,3, ...,10}8) A community bank studied the transaction times at the tellers' windows. Theyfound that, rounded to the nearest minute, 15% of the transactions took oneminute, 30% took two minutes, 25% took three minutes, 20% took four minutes,and 10% took five minutes. Find the expected time of a random transaction andround your answer to the tenths place.2.8minutes3.8minutes4.8minutes5.8minutes9) Which of the following statement(s) is(are) a characteristic(s) of a binomial experiment?A. The experiment consists of 'n' identical trials.B. Each trial results in one of two outcomes, 'success' or'failure'.C. The probability of success on a single trial is equal to 'p'and remains the same from trial to trial. The probabilityof failure is equal to q = (1 - p).D. The trials are independent.E. We are interested in 'x', the number of successesobserved during the 'n' trials, for x = 0, 1, 2, ..., n. All of the above are characteristics of a binomial experiment.Only some of the above are characteristics of a binomial experiment.None of the above are characteristics of a binomial experiment.10)The taste test for PTC (phenylthiourea) is a common class demonstration in thestudy of genetics. It is known that 70% of the American people are “tasters” with the restare “non-tasters”. Suppose a genetics class of size 20 does the test to see if they match theAmerican percentage of “tasters” and “non-tasters”. Assume that the assignment ofstudents to classes is a random process. Calculate the mean.3671411)From past experience, it is known that 90% of one-year-old children candistinguish their mother’s voice from the voice of a similar sounding female. A randomsample of 20 one-year-old children are given this voice recognition test. Calculate thevariance.0.20.91.83.912)A quiz consists of 30 questions. Each question has 3 answer choices with exactlyone correct answer. A student is completely unprepared for the quiz, so he guesses on all30 questions. How many questions should the student expect to answer correctly?1013151824 13)A quiz consists of 18 questions. Each question has 3 answer choices with exactlyone correct answer. A student is completely unprepared for the quiz, so he guesses on all18 questions. How many questions should the student expect to answer incorrectly?689121814)It is known that 10% of the customers in an electronics store purchase an MP3player. A random sample of 30 customers is selected. Assume that the customers’purchases are made independently. What is the definition of “success” in this binomialdistribution application?

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