91影视

Number of premature infants is $77$

PGM group is $20$

Other treatments is$19$

The number of males is the number in the group decreased by the number of females

The proportions in each group is the number of infants divided by the row total given in the last column:

The proportions appears to be balanced, because there are no large differences between the proportions.

The number of premature infants is $77$

PGM group is $20$

Other treatments is$19$

Observed counts

The expected counts are the row total multiplied by the column total, divided by the sample size$n=77$

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

localid="1650644257312" $$\begin{gathered} {蠂}^2=\frac{(9-9.0909{)}^2}{9.0909}+\frac{(8-8.6364{)}^2}{8.6364}+\frac{(8-8.6364{)}^2}{8.6364}+\frac{(10-8.6364{)}^2}{8.6364} \\ +\frac{(11-10.9091{)}^2}{10.9091}+\frac{(11-10.3636{)}^2}{10.3636}+\frac{(11-10.3636{)}^2}{10.3636}+\frac{(9-10.3636{)}^2}{10.3636} \\ =0.5683 \end{gathered}$$

The interval for the P-value can then be found in table C in the column title which has the $X^2$-value in the corresponding interval in the row with

localid="1650644276147" $$\begin{gathered} df=(c-1)(r-1) \\ =(4-1)(2-1) \\ =3 \end{gathered}$$

localid="1650644291222" $p>0.25$

If the P-value is smaller than the significance level, then the null hypothesis is rejected.

$P>0.05鈬�Failtoreject{H}_0$

There is not sufficient evidence that there is an association between the variables.