A machine is set to produce tennis balls so the mean bounce is 36 inches when the ball is dropped from a platform of a certain height. The production supervisor suspects that the mean bounce has changed and is less than 36 inches. As an experiment, a sample of 12 balls was dropped from the platform and the mean height of the bounce was 35.5 inches, with a standard deviation of 0.9 inch. At the .05 significance level, can the supervisor conclude that the mean bounce height is less than 36 inches?

(a) The null and the alternate hypotheses,

(b) The decision rule, and

(c) The decision regarding the null hypothesis,

(d) Then interpret the result.