Suppose that all the students registered to the probability and statistics course have to buy textbook. The 28 % of all students demand a new book, on the other hand the other 72 % want a used text book. Consider randomly selecting 40 purchasers. a. What are the mean value and standard deviation of the number who want a new copy of the book? b. What is the probability that the number who want brand-new books is more than 1.5σ away from the mean value? c. The bookstore has 30 new and 30 used textbooks in stock. If 40 people come in one by one to purchase this text, what is the probability that all 40 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 40 get what they want?]
Suppose that all the students registered to the
a. What are the
book?
b. What is the probability that the number who want brand-new books is more than 1.5σ away
from the mean value?
c. The bookstore has 30 new and 30 used textbooks in stock. If 40 people come in one by one to
purchase this text, what is the probability that all 40 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 40
get what they want?]
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