MATH 120 WEEK 5 EXAM NEWLY UPDATED
QUESTIONS AND ANSWERS WITH FULL
SOLUTIONS – 2026 GUARANTEED SUCCESS
Distributions of Data Exam
100%
1.
Using the test scores in the table below, what is the variance of the scores on the exam?
(Round your answer to the nearest whole number.)
18
21
24
27
31
2.
Using the test scores in the table below, what is the standard deviation of the scores on
the exam? (Round your answer to the nearest whole number.)
3
5
, 6
7
9
Explanation:
Determine that the average score is 87%
Calculate all of the differences between the scores and the average to get 9, 5, 4, 3, 0, -
1, -1, -4, -5, -10
Square all of the differences to get 81, 25, 16, 9, 0, 1, 1, 16, 25, 100
Average the squared differences to get 27.4 as the variance
Take the square root of the variance to get 5.23 as the standard deviation
Round 5.23 to the nearest whole number to get 5 Answer:
5
3.
Assume that 500,000 people take the GED exam (high school proficiency exam) each
year and their scores form a normal distribution. If Danny scores two standard
deviations below the mean, what percentile is he?
2.5th
5.0th
12.5th 22.5th
Not enough information to determine.
4.
Assume that 500,000 people take the GED exam (high school proficiency exam) each
year and their scores form a normal distribution. If Tara scores one standard deviation
above the mean, what percentile is she?
34th
68th
84th
95th
Not enough information to determine.
5.
Assume that 20 people take a math test, which is not enough for a normal distribution to
form. If Conrad scores three standard deviations above the mean, what percentile is he?
75.0th
88.5th
95.0th 99.7th
Not enough information to determine.
6.
Assume that 20 people take a math test, which is not enough for a normal distribution to
form. If Sarah scores at the median, what percentile is she?
34th
50th
QUESTIONS AND ANSWERS WITH FULL
SOLUTIONS – 2026 GUARANTEED SUCCESS
Distributions of Data Exam
100%
1.
Using the test scores in the table below, what is the variance of the scores on the exam?
(Round your answer to the nearest whole number.)
18
21
24
27
31
2.
Using the test scores in the table below, what is the standard deviation of the scores on
the exam? (Round your answer to the nearest whole number.)
3
5
, 6
7
9
Explanation:
Determine that the average score is 87%
Calculate all of the differences between the scores and the average to get 9, 5, 4, 3, 0, -
1, -1, -4, -5, -10
Square all of the differences to get 81, 25, 16, 9, 0, 1, 1, 16, 25, 100
Average the squared differences to get 27.4 as the variance
Take the square root of the variance to get 5.23 as the standard deviation
Round 5.23 to the nearest whole number to get 5 Answer:
5
3.
Assume that 500,000 people take the GED exam (high school proficiency exam) each
year and their scores form a normal distribution. If Danny scores two standard
deviations below the mean, what percentile is he?
2.5th
5.0th
12.5th 22.5th
Not enough information to determine.
4.
Assume that 500,000 people take the GED exam (high school proficiency exam) each
year and their scores form a normal distribution. If Tara scores one standard deviation
above the mean, what percentile is she?
34th
68th
84th
95th
Not enough information to determine.
5.
Assume that 20 people take a math test, which is not enough for a normal distribution to
form. If Conrad scores three standard deviations above the mean, what percentile is he?
75.0th
88.5th
95.0th 99.7th
Not enough information to determine.
6.
Assume that 20 people take a math test, which is not enough for a normal distribution to
form. If Sarah scores at the median, what percentile is she?
34th
50th
