Question

The marketing department of a manufacturing company wanted to find out how many blank video cassettes are purchased by the average American each year. The data for a random sample of Americans are as follows: 7, 0, 6, 3, 10, 0, 4, 9, 6, 3, 12, 0, 5, 1, 8, 6 (n = 16). What are the limits of the 99% confidence interval for the mean of the population? PLEASE SHOW ALL WORK!

Answer 1

We have for given data,      
          
Sample mean =5  
Sample standard deviation =3.71
Sample size =16  
Level of significance=1-0.99=0.01  
Degree of freedom =15  
          
t critical value is (by using t table)=   2.947  
          
Confidence interval formula is           


=(2.2667,7.7333)      
          
          
Lower confidence limit=2.27  
          
Upper confidence limit=7.73