College Math Placement Test Statistics 5

Question 1

A data set has mean 50 and standard deviation 10. A value of 70 has a z-score of:

Accepted Answer

2

Answer

z = (70 − 50) / 10 = 20/10 = 2.

Question 2

If events A and B are independent and P(A) = 0.4, P(B) = 0.5, what is P(A and B)?

Accepted Answer

0.2

Answer

For independent events, P(A and B) = P(A) × P(B) = 0.4 × 0.5 = 0.2.

Question 3

A histogram with bars of roughly equal height suggests the distribution is:

Accepted Answer

Uniform

Answer

Equal bar heights indicate that all values occur with similar frequency, which is characteristic of a uniform distribution.

Question 4

The stem-and-leaf plot shows stems 1, 2, 3 with leaves 2 3 | 1 4 6 | 0 5. What is the median?

Accepted Answer

24

Answer

The values in order are 12, 13, 21, 24, 26, 30, 35; the 4th (middle) value is 24.

Question 5

A confidence interval is reported as (48, 56). What is the margin of error?

Accepted Answer

4

Answer

The margin of error is half the width of the interval: (56 − 48) / 2 = 4.

College Math Placement Test Practice Test