When 40 people used the Weight Watchers diet for one year, their mean weight loss was 3.0 lbs. and the standard deviation was 4.9 lbs (Dansinger et al, 2005). Round all values to the hundredths.

a)Is this a t-test or a z-test? How do you know?

b)Use a 0.01 significance level to test the claim that the mean weight loss is greater than 0.

What are the hypotheses?

What is the test statistic?

What is the critical value(s)?

What was your decision?

State your conclusion.

c)There is a difference between statistical significance and practical significance. Which, if any, did this study show? Support your answer by reference the test and the findings.