Question

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

33

24

31

34

28

29

20

33

33

29

43

32

33

22

a. Construct a

99​% confidence interval estimate for the population mean MPG for this type of​ vehicle, assuming a normal distribution.The 99%

confidence interval estimate is from____MPG to ____MPG.

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

Answer 1

Sample size = n = 14

Sample mean = = 30.2857

Standard deviation = s = 5.7570

We have to construct 99% confidence interval.

Formula is

Here E is a margin of error.

Degrees of freedom = n - 1 = 14 - 1 = 13

Level of significance = 0.01

tc = 3.012    ( Using t table)

So confidence interval is ( 30.2857 - 4.6347 , 30.2857 + 4.6347) = > ( 25.7 , 34.9)