doctor has developed a new diet to help people lose weight. A random sample of 500 people went on the diet for six weeks. The mean number of pounds lost was x̄ = 0.5.

Assume the standard deviation is σ = 5.

Let μ be the population mean number of pounds lost. To determine whether the diet is effective, a test is made of the hypotheses H0: μ = 0 versus H1: μ > 0.

a. Compute the value of the test statistic.

b. Compute the P-value.

c. Do you reject H0 at the α = 0.05 level?

d. Is the result of practical significance? Explain.