Question

If n=13, ¯(x-bar)=47, and s=2, construct a confidence interval at a 99% confidence level. Assume the data came from a normally distributed population. Give your answers to one decimal place

Answer 1

We have given that,              
              
Sample mean =47      
Sample standard deviation =2  
Sample size =13      
Level of significance=1-0.99=0.01      
Degree of freedom =12      
              
t critical value is (by using t table)=   3.055      
              
Confidence interval formula is               


=(45.3,48.7)          
              
              
Lower confidence limit=   45.3  
              
Upper confidence limit=   48.7