Question

S

The sath-grade students at Jefferson Middle School took a survey for health cass. As part of
the survey, they were asked to record how long they spent brushing their teeth before school
one morning. This box plot shows the results.
Time brushing teeth (sec.)
60
80
100
120
140
What percent of the students spent 50 seconds or longer brushing their teeth?

Answer 1

100%

Explanation:

Because all the time results are higher than 50 second.

Answer 2

75%

Explanation:

A box plot shows the minimum, lower quartile, median, upper quartile, and maximum of a data set.

Find the part of the box plot that represents 60 seconds or longer.

Time brushing teeth (sec.)

40

60

80

100

120

140

In a box plot, the box represents the middle 50% of the data. Each whisker represents 25% of the data. Add to find what percent of the box plot represents 60 seconds or longer.

50%+25%=75%

So, 75% of the students spent 60 seconds or longer brushing their teeth that morning.