1. Box-and-Whisker Plots
Algebra 1B Lesson 40 instructional material 1

2. Box-and-Whisker Plot
A box-and-whisker plot is a way to display data. The box-and-whisker plots shows the median, lower and upper quartiles, and lower and upper extremes.

3. Parts of a Box-and-Whisker Plot
The median is the middle number when the data set is in order from least to greatest.
The lower quartile is the median of the lower half of the numbers.
The upper quartile is the median of the upper half of the numbers.
The lower extreme is the lowest number in the data set.
The upper extreme is the highest number in the data set.

4. Cont.

5. More Parts of Box-and-Whisker
The range is the difference in the upper and lower extremes.
The interquartile range is the difference in the upper and lower quartiles.

6. Percentiles
The whole box-and-whisker plots represents 100% of the data.
Each section of the plot represents 25% of the data.

7. Example 1

8. Example 2
Refer to the box & whisker graph below that shows how much time was spent per night on homework for sophomore class at a certain high school during September.

9. Cont.
Identify if each statement is true, false, or cannot be determined.
________ 1. Some sophomores didn’t watch TV that month.   
________ % of the sophomores spend between 48 & 60 minutes per night on homework.
________ % of the sophomores didn’t watch TV that month.
________ 4. In general, these sophomores spend more time watching TV than doing homework.
________ 5. The range of the time spent watching TV is less than the range for the time spent doing homework.

10. Example 3

11. Cont.