## Elementary Statistics (12th Edition)

$H_{0}:\mu_d=0,$ $H_{a}:\mu_d\ne0$. The test statistic is:$t=\frac{\overline{d}-\mu_d}{s_d/\sqrt{n}}=\frac{-0.33-0}{0.7435/\sqrt{20}}=-1.985.$ The P is the corresponding probability using the table with df=20-1=19, hence P is between 0.05 and 0.1. If the P-value is less than $\alpha$, which is the significance level, then this means the rejection of the null hypothesis. Hence:P is more than $\alpha=0.05$, hence we fail to reject the null hypothesis. Hence there seems to be no difference in temperature.