AP Stats Descriptive Statistics 2

Question 1

A dataset has a mean of 50 and a standard deviation of 10. What is the z-score of the value 35?

Accepted Answer

-1.5

Answer

z = (35 - 50) / 10 = -15/10 = -1.5.

Question 2

Which measure of spread is most affected by extreme outliers?

Accepted Answer

Range

Answer

The range uses only the minimum and maximum values, so a single extreme outlier directly changes it.

Question 3

In a right-skewed distribution, which ordering is typically correct?

Accepted Answer

Mean > Median > Mode

Answer

Right skew pulls the mean toward the tail, so mean exceeds median, which exceeds mode.

Question 4

A five-number summary shows Min=10, Q1=25, Median=40, Q3=55, Max=100. What is the IQR?

Accepted Answer

30

Answer

IQR = Q3 - Q1 = 55 - 25 = 30.

Question 5

Which graphical display is best for comparing the distribution shapes of two groups side by side?

Accepted Answer

Back-to-back stemplot

Answer

A back-to-back stemplot shares a common stem and shows both distributions' shapes simultaneously.

AP Practice Test