1. Ch. 12 Vocabulary 15.) quartile 16.) Interquartile range
17.) Box and whisker plot
18.) percentile
19.) percentile rank

2. 12-4 Box & Whisker Plots
Algebra 1

3. Hints for making a box-and-whiskers plot:
Make sure data is in order from least to greatest.
Find the minimum value, median, maximum value, upper & lower quartiles information first.
Plot the points for this info below a number line.
Then, draw box and whiskers.

4. Ex. 1 –Find the min., 1st Q, Median, 3rd Q, and max. of each data set.
17, 24, 25, 30, 33, 34, 36, 37, 39, 40, 40, 42, 48
Draw the box and whiskers.

5. Box-and-whisker plots
Minimum value (17)
Maximum value (48)
Median (36)
Lower Quartile – median of all numbers in the list to the left of the median
(25+30)/2 = 27.5
Upper Quartile – median of all numbers to the right of the median
(40+40)/2 = 40

6. Percentiles of a box & whisker plot
Percentiles – separate data sets into equal parts

7. Ex. 2) Find the information 7, 8, 9, 10, 12, 14, 15, 16

8. Finding a percentile rank
Percentile rank of a data value is the percentage of data values that are less than or equal to that value.

9. Ex. 3
Of 25 test scores, fifteen scores are less than or equal to 85. What is the percentile rank of 85?
15/25=