91影视

The given data is

Observed counts

Expected counts

The expected counts are the row total multiplied by the column total, divided by the sample size$n=6602$

The chi-square statistic is the sum of squared deviations (between observed and expected counts) divided by the expected count:

localid="1650645457450" $$\begin{gathered} {蠂}^2=\frac{(250-205.8128{)}^2}{205.8128}+\frac{(206-205.8128{)}^2}{205.8128}+\frac{(211-206.4368{)}^2}{206.4368}+\frac{(157-205.9376{)}^2}{205.9376} \\ +\frac{(1399-1443.1872{)}^2}{1443.1872}+\frac{(1443-1443.1872{)}^2}{1443.1872}+\frac{(1443-1447.5632{)}^2}{1447.5632}+\frac{(1493-1444.0624{)}^2}{1444.0624} \\ =9.487+0+0.101+11.629+1.353+0+0.14+1.658 \\ =24.243 \end{gathered}$$

It is noted that we obtained the largest chi-square subtotals for the Placebo and Both. This means that Both medicines together lead to better results and thus this treatment should be used (if the side effects are not too significant).