H0 : = 400

H1 : 400

A random sample of 12 observations is selected from a normal population. The sample mean was 407 and the sample standard deviation 6. Using the .01 significance level:

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

Reject H0 when the test statistic is outside the interval ( , ).

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