Two Cal Poly freshmen gathered data on a random sample of textbooks from the
campus bookstore in November of 2006. Two of the variables recorded were the
price of the book and the number of pages that it contained. These data are in
the fi le Text book Prices.
a. Describe the population slope in the context of the study
and assign a symbol to it.
Â b. Suppose that you want to test whether there is a
positive association between price and number of pages in the population of all
textbooks for sale in the bookstore in November of 2006. State the appropriate
null and alternative hypotheses in terms of the population slope using the
symbol used in part (a).
c. Is a theory-based test appropriate? Why or why not?
d. Determine and report the value of the t-statistic and
p-value for testing the hypotheses stated in part (b).
e. Do the sample data provide strong evidence that number of
pages is a significant predictor of price? Explain how you can tell.
f. Determine and interpret a 95% confidence interval for the
value of the population slope.