Given the following hypotheses:

H0: μ = 470
H1: μ ≠ 470

A random sample of 13 observations is selected from a normal population. The sample mean was 475 and the sample standard deviation 9. Using the 0.05 significance level:

a. State the decision rule. (Negative amount should be indicated by a minus sign. Round your answers to 3 decimal places.)

b. Compute the value of the test statistic. (Round your answer to 3 decimal places.)