Question

the dot plots represent the distribution of values in data sets a and b. which of the following statements must be true?
i the median of data set a is equal to the median of data set b
ii the standard deviation of data set a is equal to the standard deviation of data set b
a. i and ii
b. i only
c. ii only
d. neither i nor ii
data set a
value
4 •
5 • • •
6 • •
7 • • •
8 • •
9 • • •
10 •
data set b
value
4 • •
5 • • •
6 • •
7 • • •
8 • •
9 • • •
10 •

Explanation:

Step1: Recall definitions

Median is the middle - value when data is ordered. Standard deviation measures the spread of data.

Step2: Analyze dot - plots

Just because the median of data set A is equal to the median of data set B does not imply that the standard deviation of data set A is equal to the standard deviation of data set B. The spread of data points around the median can be different in the two data sets.

Answer:

d. Neither I nor II