Suppose that a student needs to buy 6 books for her history ...

[Lisaclaire]

Suppose that a student needs to buy 6 books for her history course. The number of books that she will be able to find used is a binomial random variable X with n = 6 and p = 0.30 . In other words, the probability that she will find any given book used is 0.30, and is independent from one book to the next. What is the variance for the number of used books she will find, V(X)?
 a. 0.54
  b. 1.12
  c. 1.26
  d. 61.80

Question 2

A television station plans to ask a random sample of 400 city residents if they can name the news anchor on the evening news at their station. They plan to fire the news anchor if fewer than 10 of the residents in the sample can do so. Suppose that 12 of city residents in the sample could name the anchor when asked. Explain in your own words what the 95 confidence level implies.

[hramirez205]

Answer to Question 1

C

Answer to Question 2

If repeated samples of size 400 were taken, 95 of the resulting confidence intervals would contain the population proportion of city residents who can name the news anchor on the evening news at their station.