In an effort to find a method of predicting the dental work required by army recruits, an army dentist studies the dental records of a random sample of 10 recruits completing their service. She computes the relationship between the number of cavities filled in the first two years of service y with the number of cavities filled in the two years before service x.
a. State the null hypothesis that should be used to test for the usefulness of the regression line.
b. Give the alternative hypothesis you would suggest to the dentist and the reason for that alternative.
c. Give the critical value.