Question

You intend to estimate a population mean μμ with the following sample.

77.3

78.3

103.3

78.4

70.4

75.1

69.8

80.4

73.3

52.6

91.9

You believe the population is normally distributed. Find the 99.5% confidence interval. Enter your answer as an open-interval (i.e., parentheses) accurate to twp decimal places (because the sample data are reported accurate to one decimal place).

99.5% C.I. =

Answer should be obtained without any preliminary rounding. However, the critical value may be rounded to 3 decimal places.

Answer 1

We have for given data,          
              
Sample mean =77.3455      
Sample standard deviation =12.79  
Sample size =11      
Level of significance=1-0.995=0.005      
Degree of freedom =10      
              
t critical value is (by using t table)=3.581      
              
Confidence interval formula is               


=(63.54,91.16)