Critical Region Method: Student’s t Table 4 of the Appendix gives critical values for the Student’s t distribution. Use an appropriate d.f. as the row header.

For a right-tailed test, the column header is the value of a found in the one-tail area row. For a left-tailed test, the column header is the value of a found in the one-tail area row, but you must change the sign of the critical value t to t.

For a two-tailed test, the column header is the value of a from the two-tail area row. The critical values are the t values shown. Solve Problem 12 using the critical region method of testing. Compare your conclusion with the conclusion obtained by using the P-value method. Are they the same?