A study of the effect of television commercials on $12-$year$-$old children measured their attention span, in seconds. The commercials were for clothes, food, and toys.

Compute the $95\%$ confidence intervals that estimate the difference between each pair of means.

g$.$ Compute the $95\%$ confidence intervals that estimate the difference between each pair of means. $($Negative amount should be indicated by a minus sign. Round your answers to $2$ decimal places.$)$ How is this done with Excel Data Anyalsis or MegaStat?