Question

Service NSW has customers fill out a satisfaction survey from 0 through 10 (0: not satisfied, 10: extremely satisfied) as they leave the building. The following random sample of 15 customers was drawn. {1, 9, 10, 1, 8, 5, 3, 3, 2, 7, 8, 3, 9, 8, 5} What is the 95% confidence interval for μ ? Select one:

a. (3.7, 7.2)

b. (4.1, 6.9)

c. (5.1, 6)

d. (2.9, 8.1)

e. None of the above.

Answer 1

We have for given data,              
              
Sample mean =5.47      
Sample standard deviation =3.14  
Sample size =15      
Level of significance=1-0.95=0.05      
Degree of freedom =14      
              
t critical value is (by using t table)=   2.145      

a. (3.7, 7.2)