Question

Which statement best describes the data used to create the box plot shown below?

The mean of the data set is 4.
The majority of the data points lie between 3 and 9.
The data set has more values between 9 and 15 than it does between 1 and 3 D. There are as many data points between 3 and 4 as there are between 4 and 9.

Answer 1

D

Explanation:

To understand this, let's think about what a box plot is.

• The line in the middle is the median, or the 50% line.
• The box is the IQR, and the ends of the box are the first quartile (Q1) and the third (Q3). 50% of the data is in the box.
• The endpoints are the largest and smallest data values that aren't outliers (and it looks like there are no outliers, because I don't see any dots or stars on the outside of the plot).

Why not A: That's the median, not the mean.

Why not B: The box tells us that exactly 50% of the data lies between 3 and 9. I wouldn't call that a "majority."

Why not C: The distance from 9 and 15 makes up 25% of the data, as does that between 1 and 3.

Answer 2

B. the majority of the data points lie between 3 & 9.