9
Since the distribution is skewed to the right we know that the mean should be to the right of the
median. We know that the median has to be in the interval (75, 80] or in the interval (80,85] depending
on the exact values of the 10
th
observation (<= 80) and the 11
th
observation (>80). Since we don’t know
the location of the median relative to 80 we don’t know the position of the mean relative to 80.
23.
What percent of the students scored below 80?
A.
At least 50%
B.
50%
C.
At most 50%
D.
NONE OF THESE THREE
We know that the number of students scoring below OR EQUAL to 80 is 10. So the number of
students scoring below 80 should be 10 or less.
24.
Below is a list of gas mileage ratings for selected passenger cars in miles per gallon: 53, 43, 89, 41, 85,
86, 91, 92, 95, 94, 86, 102, 114, 30, 123. Make a boxplot to represent this data.
Data in increasing order: 30, 41, 43, 53, 85, 86, 86, 89, 91, 92, 94, 95, 102, 114, 123. There are 15
observations. The 8
th
is the median = 89. The 4
th
is Q1 = 53. The 12
th
is Q3 = 95. Min = 30, Max = 123.
140
120
100
80
60
40
20
25.
Create a set of five positive numbers that have median 6 and mean 10.