Fast Food
the General Manager of a Chain of Fast

Fast Food
The general manager of a chain of fast food chicken restaurants wants to determine how effective their promotional campaigns are.In these campaigns "20% off" coupons are widely distributed.These coupons are only valid for one week.To examine their effectiveness,the executive records the daily gross sales (in $1,000s)in one restaurant during the campaign and during the week after the campaign ends.The data is shown below. $$\begin{array} { | l | c | c | } \hline { \text { Day } } & \begin{array} { c } \text { Sales During } \\\text { Campaign }\end{array} & \begin{array} { c } \text { Sales After } \\\text { Campaign }\end{array} \\\hline \text { Sunday } & 18.1 & 16.6 \\\text { Monday } & 10.0 & 8.8 \\\text { Tuesday } & 9.1 & 8.6 \\\text { Wednesday } & 8.4 & 8.3 \\\text { Thursday } & 10.8 & 10.1 \\\text { Friday } & 13.1 & 12.3 \\\text { Saturday } & 20.8 & 18.9 \\\hline\end{array}$$
-Estimate with 95% confidence the mean difference.