Left-tailed test

we want to know if $\overline{x}$ is significantly less than $\mu_0$ .

confidence interval method: If the lower limit of the confidence interval for the population mean $\mu$ (cell E27) is smaller than $\mu_0$ (the population mean when the null hypothesis is true), accept the null hypothesis. Otherwise, reject it (the appropriate conclusion appears in cell E28).

classic method: If the $t$ -statistic (cell B10) is greater than $-t_{\alpha}$ , accept the null hypothesis. Otherwise, reject it (the appropriate conclusion appears in cell E19).

$P$ -value method: If the probability of obtaining a $t$ -statistic as large as the one in cell B10 or larger in absolute value is less than $\alpha$ , reject the null hypothesis. Otherwise, accept it (the appropriate conclusion appears in cell E22).