WGU C955 Probability and Statistics Pre Assessment Exam
Questions and Answers (Verified by Expert) Newest Update
2026/2027.
1. In a class of 25 students, the following test scores were obtained:
31, 46, 49, 52, 55, 67, 68, 68, 69, 69, 71, 73, 73, 75, 75, 78, 79, 82, 84, 84, 85, 87,
91, 92, 97
Which statement is true about this distribution ANS The distribution is skewed
to the left.
2. In a class of 25 students, the following test scores were obtained:
51, 59, 59, 59, 67, 68, 68, 69, 69, 71, 73, 73, 75, 75, 78, 79, 82, 84, 85, 85, 87, 91,
92, 93, 93
A histogram of interval width 10 starting with the interval [50, 60] was
constructed using the above data.
Which statement is true about this distribution as depicted by the his-
togram ANS It is a unimodal symmetric distribution.
1/8
,3. The following 5-number summaries were obtained for two distributions, A
and B:
A 3.2 4.9 5.7 5.9 8.2
B 2.7 5.1 5.7 6.9 7.5
The distribution of A is skewed to the right, whereas the distribution of B is
skewed to the left.
How are the means of the two distributions related ANS The mean of A is
higher than the mean of B.
3. In a class of 25 students, the following scores were received on a quiz:
3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9
For this distribution, what is the most appropriate measure of central
tenden- cy ANS Either the mean or the median
5. A study is conducted to determine if there is a difference in final exam
scores in high school classrooms when different types of instruction are
used. The two types of instruction included in the study are direct
instruction and computer-based instruction.
2/8
, What are the explanatory (X) and response (Y) variables for this study ANS
The type of instruction is the explanatory variable (X) and the test score is the
response variable (Y).
7. A local ice cream shop kept track of the number of cans of cold
carbonated beverages it sold each day (Y) and the temperature that day (X)
for 2 months during the summer.
The data are displayed in the following scatterplot:
Which statement describes the relationship between X and Y as it appears
in the scatterplot ANS If the outlier were removed, r would increase.
8. The following table shows the age of a child in months (x) and the hours
of sleep the child needs during nap time each day (y).
Age Nap Time
3/8
Questions and Answers (Verified by Expert) Newest Update
2026/2027.
1. In a class of 25 students, the following test scores were obtained:
31, 46, 49, 52, 55, 67, 68, 68, 69, 69, 71, 73, 73, 75, 75, 78, 79, 82, 84, 84, 85, 87,
91, 92, 97
Which statement is true about this distribution ANS The distribution is skewed
to the left.
2. In a class of 25 students, the following test scores were obtained:
51, 59, 59, 59, 67, 68, 68, 69, 69, 71, 73, 73, 75, 75, 78, 79, 82, 84, 85, 85, 87, 91,
92, 93, 93
A histogram of interval width 10 starting with the interval [50, 60] was
constructed using the above data.
Which statement is true about this distribution as depicted by the his-
togram ANS It is a unimodal symmetric distribution.
1/8
,3. The following 5-number summaries were obtained for two distributions, A
and B:
A 3.2 4.9 5.7 5.9 8.2
B 2.7 5.1 5.7 6.9 7.5
The distribution of A is skewed to the right, whereas the distribution of B is
skewed to the left.
How are the means of the two distributions related ANS The mean of A is
higher than the mean of B.
3. In a class of 25 students, the following scores were received on a quiz:
3, 3, 3, 3, 4, 4, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 9, 9, 9, 9
For this distribution, what is the most appropriate measure of central
tenden- cy ANS Either the mean or the median
5. A study is conducted to determine if there is a difference in final exam
scores in high school classrooms when different types of instruction are
used. The two types of instruction included in the study are direct
instruction and computer-based instruction.
2/8
, What are the explanatory (X) and response (Y) variables for this study ANS
The type of instruction is the explanatory variable (X) and the test score is the
response variable (Y).
7. A local ice cream shop kept track of the number of cans of cold
carbonated beverages it sold each day (Y) and the temperature that day (X)
for 2 months during the summer.
The data are displayed in the following scatterplot:
Which statement describes the relationship between X and Y as it appears
in the scatterplot ANS If the outlier were removed, r would increase.
8. The following table shows the age of a child in months (x) and the hours
of sleep the child needs during nap time each day (y).
Age Nap Time
3/8
