Question

A simple random sample of size n =24 is drawn from a population that is normally distributed. The sample mean is found to be x overbar equals 58 and the sample standard deviation is found to be s=12. Construct a 90​% confidence interval about the population mean.

The lower bound is?

The upper bound is?

Answer 1

We have given that,          
          
Sample mean =58  
Sample standard deviation =12
Sample size =24  
Level of significance=   1-0.90=0.1  
Degree of freedom =23  
          
t critical value is (by using t table)=   1.714  
          
Confidence interval formula is           


=(53.8016,62.1984)      
          
          
Lower confidence limit=   53.80
          
Upper confidence limit=   62.20