Preliminary Data Analyses Indicates That Use of a Paired T-Test $\mathrm { H } _ { 0 } : \mu _ { 1 } = \mu _ { 2 }$

Preliminary data analyses indicates that use of a paired t-test is reasonable. Perform the hypothesis test by using eitherthe critical-value approach or the P-value approach as indicated. Assume that the null hypothesis is $\mathrm { H } _ { 0 } : \mu _ { 1 } = \mu _ { 2 }$
-Ten different families are tested for the number of gallons of water a day they use before and after viewing a conservation video. The results are shown below. $\begin{array} { l c c c c c c c c c c } \text { Before } & 33 & 33 & 38 & 33 & 35 & 35 & 40 & 40 & 40 & 31 \\ \hline \text { After } & 34 & 28 & 25 & 28 & 35 & 33 & 31 & 28 & 35 & 33 \end{array}$ At the 5% significance level, do the data provide sufficient evidence to conclude that the mean amount of water use after the viewing differs from the mean amount of water use before the viewing? Use the critical-value approach.