1. Box & Whisker Plots

2. Box and Whisker plots are created using a 5-number summary of the:
minimum,
maximum,
median,
first quartile and
third quartile.

3. Directions:
Put the numbers in order from small to big.
Determine the maximum & minimum values.
Find the median value by crossing off the values on the left & right until you find the number or numbers in the middle.
To find the first quartile find the middle of the first half of the data.
If you have an off number of values and your median value was a single point…. You need to reuse that number to find your Q1.
To find the third quartile find the middle of the second half of the data.
If you have an off number of values and your median value was a single point…. You need to reuse that number to find your Q3.

4. Example #1:
Shown below are the scores 16 students received on a math quiz. Create a box plot of the data.
52, 60, 66, 66, 68, 72, 72, 73, 74, 75, 80, 82, 84, 91, 92, 98

5. Example #2:
The ages of 15 employees of the Red Hook Curry House are given below.
16, 17, 17, 18, 19, 22, 25, 26, 29, 33, 33, 37, 40, 42, 44

6. Box and whisker plots are split up into quartiles or QUARTERS
Box and whisker plots are split up into quartiles or QUARTERS. Which means, there are 4 sections and they each represent 25% of the data!

7. Example #3:
Twenty of Mr. Smith’s physics students recently took a quiz. The results of this quiz are shown in the following box & whisker plot. Assume that all scores are whole numbers.
What was the median score on Mr. Smith's quiz?
What was the range of scores on the quiz?
What score was greater than or equal to 75% of all the other scores?

8. Example #3:
Twenty of Mr. Smith’s physics students recently took a quiz. The results of this quiz are shown in the following box & whisker plot. Assume that all scores are whole numbers.
What percentage of kids score between 64 and 76?
Mr. Smith regularly sets the passing grade on his quizzes to be the lower quartile. What is the passing grade on this quiz?

9. Example #4
The speeds in miles per hour of 24 cars on a road are recorded and represented on the box-and-whisker plot shown below.
What is the range of speeds?
What is the maximum speed of the 24 drivers?
How many drivers drove between 30 and 42 miles per hour?
If the speed limit on this part of the road is 35 miles per hour, are more people speeding or are more people going the speed limit? Justify your answer.