Sec. 3-5Exploratory Data Analysis

1. Stem & Leaf Plots: (relates to Freq. Dist)

Look at examples on page 131-133.

2. Box Plot: (Relates to Histograms)

A visual layout of how your data is spread. It shows your Interquartile Range. (IQR Relates to standard deviation it represents the middle 50% of your data.)

You find the min., max, Q1, Q2, & Q3.

***Never “use” the Q2 when finding the Q1 & Q3.

Suppose you had the following data:

22, 24, 35, 48, 31, 27, 30, 44, 43, 22, 25

Put the data in order first.

22, 22, 24, 25, 27, 30, 31, 35, 43, 44, 48

Q2 = 30

Next, find Q1 & Q3 NOT USING Q2

Q1 = 24 & Q3 = 43

Q1 & Q3 will form your LEFT & RIGHT HINGES respectively.

The general shape of a Box & Whisker or BOX plot is:

Min Q1 Q2 Q3 Max

22 24 30 43 48

end

Box Plot on Calculator

1.STAT edit enter data

2.2nd Y= turn plot(s) ON (boxplot)

3.ZOOM #9

4.TRACE to see 5 number summary