4.4 OUTLIERS AND DOT PLOTS

WHAT IS AN OUTLIER?

• Sometimes, distributions are characterized by extreme values that differ greatly from the other observations. These extreme values are called outliers.

HOW DO YOU KNOW IF A DATA POINT IS AN OUTLIER?LOWER BOUNDARY

• EX 1: 16, 19, 20, 24, 28

• Would 3 be an outlier?• Would 5 be an outlier?

UPPER BOUNDARY• EX 2: 49, 65, 58, 46

• Would 80 be an outlier?

• Would 84 be an outlier?

WHAT DO OUTLIERS LOOK LIKE ON A BOX PLOT?

BOX PLOTS USED IN THE MEDICAL FIELD!

CREATE A BOX PLOT AND DETERMINE:

• Min• Q1• MED• Q3• Max• Outlier Boundaries (lower and upper)

• 16, 22, 19, 18, 12, 10, 17, 14, 18, 21, 16, 20, 20

DOTPLOT

Advantages

• See every data point• Quickly see the range

(highest and lowest point)

• Easy to see the mode (most frequent data point)

Disadvantages

• Takes a long time to construct if many data points

Test_Grades

40 50 60 70 80 90 100

Collection 1 Dot Plot

CREATING A DOT PLOT

• Create a dot plot for the following data: 52, 43, 61, 69, 69, 55, 62, 52, 47, 54, 69, 43, 53,48

STEM AND LEAF PLOTS

The Stem-and-Leaf Plot is a type of graph where the data is arranged by place value. The digits in the largest place are referred to as the stem and the digits in the smallest place are referred to as the leaf (leaves). The leaves are displayed to the right of the stem. Stem and Leaf Plots are great organizers for large amounts of information.

CREATING STEM AND LEAF PLOTS

• 15, 16, 21, 23, 23, 26, 26, 30, 32, 41

• 126, 106, 95, 114, 98, 107, 114, 128, 134, 117, 122, 129