Question

A random sample of 16 pharmacy customers showed the waiting times below (in minutes).

20, 27, 24, 23, 19, 21, 18, 17

22, 15, 18, 32, 16, 20, 19, 19

Find a 90 percent confidence interval for μ, assuming that the sample is from a normal population. (Round your standard deviation answer to 4 decimal places and t-value to 3 decimal places. Round your answers to 3 decimal places.) The 90% confidence interval _____ to _____

Answer 1

We have for given data,              
              
Sample mean =20.625      
Sample standard deviation =4.3031  
Sample size =16      
Level of significance=1-0.90=0.1      
Degree of freedom =15      
              
t critical value is (by using t table)=1.753      

The 90% confidence interval 18.739 to 22.511