# Stats: Statistical Hypothesis Testing Essay

Submitted By Louisa-Lu
Words: 2598
Pages: 11

03-27-2013

A PRIMER ON HYPOTHESIS TESTING FOR MEANS

Wanting to have as small a carbon footprint as possible, your best friend Sam Quint owns a Toyota
Prius. Quint claims that the average gas mileage of all the Priora in the world is µ = 37 miles per gallon
(MPG). (Note: according to The Boston Globe, the plural form of “Prius” is “Priora.”) You believe this figure is likely true since, along with being an expert on large sharks and fishing boats that could be bigger, Quint is reasonably knowledgeable about cars and car mileage. You currently own a Honda
Civic and are thinking of trading it in for a Prius. But your Civic gets pretty good mileage and you wouldn’t want to trade it in unless the Prius gets significantly more than 37 MPG on average.
Of course you will never know the true average gas mileage µ for Priora because you can’t examine all
Priora in the world. But you could take a random sample of Priora, calculate the average gas mileage
X for the sample, and then see what X might tell you about µ. So assume you can get a phone list of all of the Priora owners in the world. You take a random sample of n = 36 of them, call them up, and ask each what average gas mileage they get. You enter the data into Excel, and run Descriptive
Statistics. The results are as follows:
OBS
1
2
3
4
5
6
7
8
9
10
11
12

MPG
33.75
40.55
33.34
38.74
37.00
35.82
38.71
41.94
37.21
37.34
42.33
38.28

OBS
13
14
15
16
17
18
19
20
21
22
23
24

MPG
34.29
39.29
41.63
35.97
37.33
37.41
34.61
38.42
40.94
41.92
36.04
39.93

OBS
25
26
27
28
29
30
31
32
33
34
35
36

MPG
37.10
43.25
37.07
35.62
38.09
32.17
35.13
33.40
33.33
43.29
40.14
33.87

MPG
Mean
Standard Error
Median
Mode
Standard Deviation
Sample Variance
Kurtosis
Skewness
Range
Minimum
Maximum
Sum
Count
Confidence Level(95.0%)

37.6458
0.5121
37.335
#N/A
3.0728
9.4421
-0.8721
0.1615
11.12
32.17
43.29
1355.25
36
1.0397

© 2013 by the Kenan-Flagler Business School, University of North Carolina, Chapel Hill, NC 27599-3490. Not to be reproduced