Bluebook SAT Test One-Variable Data: Distributions and Measures of Center and Spread 14

Question 1

A dataset has values 11, 14, 14, 16, 19, 22. What is the median?

Accepted Answer

15

Answer

With 6 values, the median is the average of the 3rd and 4th values: (14 + 16) ÷ 2 = 15.

Question 2

A class of 20 students took a quiz. The mean score was 74. Later, it was discovered that one student's score of 44 was accidentally recorded as 84. What is the corrected mean?

Accepted Answer

72

Answer

The total sum was incorrectly 74 × 20 = 1480; corrected sum = 1480 − 84 + 44 = 1440; corrected mean = 1440 ÷ 20 = 72.

Question 3

A survey records the number of pets owned by 8 households: 0, 0, 1, 2, 2, 3, 4, 8. The outlier is 8. Which measure of center is least affected by this outlier?

Accepted Answer

Median

Answer

The median (average of 4th and 5th values = (2+2)/2 = 2) is unaffected by the outlier 8, while the mean is pulled upward.

Question 4

The heights (in cm) of six plants are 12, 15, 15, 18, 20, and 24. What is the variance of this dataset? (Round to nearest whole number.)

Accepted Answer

16

Answer

Mean = 104/6 ≈ 17.33; sum of squared deviations ≈ 91.3; variance = 91.3/6 ≈ 15.2, closest to 16.

Question 5

In a data distribution, the mean is 45 and the median is 52. This indicates the distribution is:

Accepted Answer

Left-skewed

Answer

When the mean is less than the median, the distribution is left-skewed (negatively skewed) because extreme low values pull the mean down.

Bluebook SAT Practice Test

Bluebook SAT Practice Test

Bluebook SAT Test One-Variable Data: Distributions and Measures of Center and Spread 14