Answer:
CI=[0.8592,0.9402]
Yes, Method appears to be effective.
Explanation:
-We first calculate the proportion of girls born:

Since np
, we assume normal distribution and calculate the 99% confidence interval as below:
![CI=\hat p\pm z\sqrt{(\hat p(1-\hat p))/(n)}\\\\=0.9\pm2.576\sqrt{(0.9* 0.1)/(370)}\\\\=0.9\pm 0.0402\\\\={0.8598, \ 0.9402]](https://img.qammunity.org/2021/formulas/mathematics/college/wuqrsznz2lmkipbrvvm47cscevtnlvbux8.png)
Hence, the confidence interval is {0.8598, 0.9402]
-The probability of giving birth to a girl is 0.5 which is less than the lower boundary of the confidence interval, it can be concluded that the method appears to be effective.