Question

The accompanying table shows the average price for a gallon of gas for the 50 states during April 2012.

State	Price per Gallon
Alaska	4.36
Alabama	3.79
Arkansas	3.76
Arizona	3.87
California	4.22
Colorado	3.89
Connecticut	4.17
Delaware	3.89
Florida	3.94
Georgia	3.83
Hawaii	4.61
Iowa	3.75
Idaho	3.77
Illinois	4.06
Indiana	3.95
Kansas	3.71
Kentucky	3.92
Louisiana	3.80
Massachusetts	3.91
Maryland	3.96
Maine	4.00
Michigan	3.93
Minnesota	3.72
Missouri	3.67
Mississippi	3.78
Montana	3.77
North Carolina	3.89
North Dakota	3.84
Nebraska	3.84
New Hampshire	3.87
New Jersey	3.80
New Mexico	3.79
Nevada	3.96
New York	4.15
Ohio	3.79
Oklahoma	3.68
Oregon	4.08
Pennsylvania	3.97
Rhode Island	3.98
South Carolina	3.72
South Dakota	3.82
Tennessee	3.77
Texas	3.81
Utah	3.71
Virginia	3.89
Vermont	3.99
Washington	4.13
Wisconsin	3.84
West Virginia	3.94
Wyoming	3.63

a.	Select a box plot for the gasoline price.

Box Plot A	Box Plot B	Box Plot C
Boxplot of Gasoline price 4.75 - 4.50 4.25 4,0。 苒 3.75 3.50

Box Plot A Box Plot B Box Plot C

b.	Use z-scores to determine if there are any outliers in the gasoline price. (Round your answers to 2 decimal places. Negative values should be indicated by a minus sign.)

The z-score for the smallest observation
The z-score for the largest observation
There are (Click to select)outliersno outliers in the data.

Answer 1

(a) Using the data and drawing the boxplot, it is observed that Boxplot B is the correct answer.

(b) Z-score is computed using the formula: (value - mean)/standard deviation = Z-score.
Z-score for smallest observation = - 1.48
Z-score for largest observation = 3.92
There are outliers in the data since the Z-score for the largest observation exceeded 3 by a large margin.