Question

The table below contains the overall miles per gallon​ (MPG) of a type of vehicle.

28

29

24

22

29

32

23

25

35

32

35

23

26

34

Construct a 95​% confidence interval estimate for the population mean MPG for this type of​ vehicle, assuming a normal distribution.The 95​% confidence interval estimate is from ____ MPG to ____ MPG.

​(Round to one decimal place as​ needed.)

Answer 1

We have for given data,              
              
Sample mean =28.36      
Sample standard deviation =4.651  
Sample size =14      
Level of significance=0.05      
Degree of freedom =13      
              
t critical value is (by using t table)=   2.16      
              
Confidence interval formula is               


=(25.7,31.0)          
              

The 95​% confidence interval estimate is from 25.7 MPG to 31 MPG.