9.81 Practice steps of test for mean For a quantitative variable, you want to test H0: m = 0 against Ha: m • 0. The 10 observations are 3, 7, 3, 3, 0, 8, 1, 12, 5, 8.

a. Show that (i) x = 5.0, (ii) s = 3.71, (iii) standard error = 1.17, (iv) test statistic = 4.26, and (v) df = 9.

b. The P-value is 0.002. Make a decision using a significance level of 0.05. Interpret.

c. If you had instead used Ha: m 7 0, what would the P-value be? Interpret it.

d. If you had instead used Ha: m 6 0, what would the P-value be? Interpret it. (Hint: Recall that the two one-sided P-values should sum to 1.)