Question

the sixth - grade students at jefferson middle school took a survey for health class. 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.) what percent of the students spent 60 seconds or longer brushing their teeth? %

Explanation:

Step1: Recall box plot properties

In a box plot, the data is divided into four quartiles, each representing 25% of the data. The left whisker represents the lowest 25% (or less) of the data, the first quartile (Q1) to median is the next 25%, median to third quartile (Q3) is another 25%, and Q3 to maximum is the last 25%. Here, the left whisker ends at 40, and the box starts at 60. So the data below 60 is the left whisker part, which is 25% (since whisker to Q1 is 25%).

Step2: Calculate percentage for 60 or longer

Total data is 100%. The percentage of data less than 60 is 25% (from whisker 40 to Q1 60). So the percentage of data 60 or longer is $100\% - 25\% = 75\%$.

Answer:

75