Aclinical trial tests a method designed to increase the probability of conceiving a girl. in the study 300 babies were born, and 270 of them were girls. use the sample data to construct a 99% confidence interval estimate of the percentage of girls born. based on the result, does the method appear to be effective?

99% confidence interval would be given (0.98;1).

We are confident that about 98% to 100% of the babies born using this new method will be girls.  So is very effective since increase the probability of getting a girl by almost the double.

Step-by-step explanation:

1) Data given and notation  

n=300 represent the random sample taken    

X=270 represent the number of girls born in the sample selected

estimated proportion of girls born with the new method

Confidence =99% or 0.99

p= population proportion of girls born with the new method proposed

2) Confidence interval

The confidence interval would be given by this formula

For the 99% confidence interval the value of and , with that value we can find the quantile required for the interval in the normal standard distribution.

And replacing into the confidence interval formula we got:

And the 99% confidence interval would be given (0.98;1.00).

We are confident that about 98% to 100% of the babies born using this new method will be girls.  So is very effective since increase the probability of getting a girl by almost the double.