Question

A dinical trial tests a method designed to increase the probabity of concaiving a git In the study 320 babies wrew born and 272 of them were girls.Use the sample data to constuct a 99% confidence interval estimate of percentage of girls born. Base on the result, does the method appears to be effective? Round to three decimal places

Answer 1

We have given,              
              
x=272          
n=320          
Estimate for sample proportion
Level of significance is =1-0.99=0.01      
Z critical value(using Z table)=2.576      
  
Confidence interval formula is              


=(0.799,0.901)              
Lower limit for confidence interval=0.799
              
Upper limit for confidence interval=0.901
Yes, the method appears to be effective.