1.For step 3, and referring to table 2 in the appendix in the textbook, the critical value for 14 degrees of freedom (15-1) and 2-sided type I error rate of 0.05 is <= -2.145 or >= 2.145.

2.For step 4, the calculation of the t statistic results in a value of -1.60.

3.Since -1.60 is not less than -2.145, we fail to reject the null hypothesis.