AST Data Analysis and Statistics

Question 1

The ages of 7 students are: 14, 16, 15, 17, 14, 18, 15. What is the median age?

Accepted Answer

15

Answer

Sorted: 14, 14, 15, 15, 16, 17, 18. The median (4th value) is 15.

Question 2

A survey found that 45% of students prefer math. If 200 students were surveyed, how many prefer math?

Accepted Answer

90

Answer

0.45 × 200 = 90 students.

Question 3

The data set {3, 7, 7, 9, 11} has a mean of 7.4. What is the range?

Accepted Answer

8

Answer

Range = highest - lowest = 11 - 3 = 8.

Question 4

Which measure of central tendency is most affected by an extreme outlier?

Accepted Answer

Mean

Answer

The mean uses all data values, so a very large or small outlier pulls it significantly.

Question 5

A scatter plot shows a strong negative correlation. This means as x increases, y:

Accepted Answer

decreases

Answer

A negative correlation means as one variable increases, the other decreases.

AST - ACT Scaling Test Practice Test