Suppose that 30% of all students who have to buy a text for a particular course want a new copy (the successes!), whereas the other 70% want a used copy. Consider randomly selecting 15 purchasers.   (a) What are the mean value and standard deviation of the number who want a new copy of the book? (Round your standard deviation to two decimal places.) (b)What is the probability that the number who want new copies is more than two standard deviations away from the mean value? (Round your answer to three decimal places.) (c) The bookstore has 10 new copies and 10 used copies in stock. If 15 people come in one by one to purchase this text, what is the probability that all 15 will get the type of book they want from current stock? [Hint: Let X = the number who want a new copy. For what values of X will all 15 get what they want?] (Round your answer to three decimal places.) (d) Suppose that new copies cost $150 and used copies cost $70. Assume the bookstore currently has 50 new copies and 50 used copies. What is the expected value of total revenue from the sale of the next 15 copies purchased? [Hint: Let h(X) = the revenue when X of the 15 purchasers want new copies. Express this as a linear function.]

For a standardized psychology examination intended for psychology majors, the historical data show that scores have a mean of 515 and a standard deviation of 175. The grading process of this year's exam has just begun. The average score of the 35 exams graded so far is 526. What is the probability that a sample of 35 exams will have a mean score of 526 or more if the exam scores follow the same distribution as in the past? Carry your intermediate computations to at least four decimal places: Round your answer to at least three decimal places. Submit Assignment 2021 McGraw Hil LLC. All Rights Reserved. Terms of Use Privacy Center Accessibility US Continue V O 8:19 hp esc 2# 8. 3 4. t 00

A dean in the business school claims that GMAT scores of applicants to the school's MBA program have increased during the past 5 years. Five years ago, the mean and standard deviation of GMAT scores of MBA applicants were 550 and 60, respectively. 30 applications for this year's program were randomly selected and the GMAT scores recorded. If we assume that the distribution of GMAT scores of this year's applicants is the same as that of 5 years ago, find the probability of erroneously concluding that there is not enough evidence to supports the claim when, in fact, the true mean GMAT score is 590. Assume αα is 0.02.

Two gamblers bet $1 each on the successive tosses of a coin: i.e., at each coin toss, player 1 pays $1 to player 2 if the coin shows ‘Heads’, and player 2 pays $1 to player 1 if the coin shows ‘Tails’. What is the mean and the standard deviation of the total winnings (measured in $, winnings can be negative) of player 1 after 6 tosses?

Business weekly conducted a survey of graduates for 30 top MBA programs.  On the basis of the survey assume the means annual salary 10 years after graduation is $162,000.  Assume the standard deviation is $40,000.  Suppose you take a simply random sample of 39 graduates.  For a single randomly selected graduate, find the probability that her salary is between $156,692.00 and $161,395.00.   For a simple random sample of 39 graduates, find the probability that the average salary is between $156,692.00 and $161,395.00.  Is the assumption of normal necessary?  Yes, or No.

Of all the students, 44% own an iPhone, with a standard deviation of .03   For that same sample of 400 students, what is the probability that at least 42% of them own an iPhone?

Suppose (rounded to the nearest thousand) that the mean cost of a house is $152,000 with a standard deviation of $44,000 in Pittsburgh and that house prices are normally distributed. Between what two prices do the middle 95% of houses fall in Pittsburgh?  Find the probability that a house costs less than $100,000.  If you are in the market for one of the most expensive 10% of houses, what price range are you exploring?