Question

The mean length of a candy bar is 43 millimeters. There is concern that the settings of the machine cutting the bars have changed. To test the claim at the 0.02 level', twelve bars (n = 12) were selected at random and their lengths in millimeters recorded. The mean of the sample is 41.5 and the standard deviation is 1.784. If the computed t = −2.913, has there been a statistically significant change in the mean length of the bars?

a. Yes, because 43 is greater than 41.5

b. Yes, because the computed t lies in the rejection region

c. Cannot be determined since z-test should be used instead of t-test

d. No, because the computed t lies in the area to the right of −2.718

e. No, because the information given is not complete

Answer 1