In: Statistics and Probability
A simple random sample of size n is drawn. The sample mean, x overbar, is found to be 18.4, and the sample standard deviation, s, is found to be 4.8.
Construct a 95% confidence interval about μ if the sample size, n, is 34.
We have given that,      
       
          
   
Sample mean =18.4      
Sample standard deviation =4.8  
Sample size =34      
Level of significance=1-0.95=0.05  
   
Degree of freedom =33      
          
   
t critical value is (by using t table)=  
2.035      
          
   
Confidence interval formula is       
       
=(16.72,20.08)