Lesson 11.2 Objective: To draw a box and whisker plot from a data list. EQ: How many sections are there in a box and whisker plot? Vocabulary: Box-and Whisker Plot: is a data display that divides a set of data into four parts. Each part represents 25% of the data. Least number 1st quartile Highest number 2nd Quartile 3rd Quartile

EX: make a box and whisker plot for the data set 5, 7, 9, 11, 11, 12, 16, 17, 19, 25, 28, 34 Third Quartile 22 First Quartile 10 Second Quartile 14 Least 5 Highest 34 5 10 14 22 34 14 is the median, 50% of the data is below while 50% is above Each section is 25 % of the data

EX: Test scores are given below, make a box and whisker plot and answer the following questions. 54, 62, 71, 74, 76, 78, 82, 82, 84, 88, 89, 90, 91, 92 , 92, 93, 95, 96 3rd quartile 1st quartile 2nd quartile 54 76 86 92 96 1) What percent scored above 76 % ? 75% 2) What percent scored above 86 % ? 50% 3) How many students scored less than 86 % ? 9 students 4) What is the range of scores ? 96 – 54 = 42 5) What is the interquartile range (3rd quartile – 1st quartile) ? 92 – 76 = 16 6) 54 is almost an outlier. Multiply 1.5 by interquartile range to determine the distance a number must be from edge of box to not be an outlier. 16 x 1.5 = 24 76 – 24 = 52 so anything less than 52 would have been an outlier.

Outliers: are numbers that are too far from the rest of the data Officially outliers are the distance more than 1.5 times interquartile range beyond the 1st or 3rd quartiles. EX: Find the median, range, quartiles, inter quartile range and outliers. Then create a box and whisker plot. 16, 18, 23, 24, 32, 39, 41, 46, 196 Outlier 1st Q 20.5 3rd Q 43.5 2nd Q 16 20.5 32 43.5 46 196 Range 180 interquartile range 23

Draw a line down middle of the plot to determine how its skewed.

After watching the video After watching the video. Be able to tell what measure of central tendency outliers have the greatest impact on.