Todays Objective

1
Todays Objective

• To construct a box and whisker plot.
• To construct a stem and leaf plot.

2
Measures of Central Tendency

• There are several methods commonly used to find
  an average.
• 1.) Mean
• 2.) Median
• 3.) Mode

3
Mean

• The mean is the sum of (n ) numbers divided by n.

4
Median

• The median is the number in middle after the
  numbers have been placed in order.

5
Mode

• The mode is the number that occurs most often.

6
Measures of Central Tendency

• Consider the numbers 84, 76, 80, 64, 92 and 84.
• Lets find the Mean, Median, and the Mode.

7
Mean

• 84 76 80 64 92 84
• 480
• 480/6 80
• The mean score is 80

8
Median

• 84, 76, 80, 64, 92, 84
• 64, 76, 80, 84, 84, 92
• Since there is no in the middle, we will find
  the median by finding the mean of the 2 s in
  the middle.

9
Median

• 64, 76, 80, 84, 84, 92
• 80 84 164
• 164/2 82
• The median score is 82.

10
Mode

• 64, 76, 80, 84, 84, 92

• The mode score is 84.

11
Measures of Central Tendency

• 64, 76, 80, 84, 84, 92
• 1.) Mean 80
• 2.) Median 82
• 3.) Mode 84

12
Find the Mean, Median, and the Mode

• 22, 34, 46, 16, 34, 28
• Mean 30
• Median 31
• Mode 34

13
Box Whisker Plots

• The median value is used to create a box
  Whisker Plot.

14
Box Whisker Plots

• 1st Quartile median of lower half
• 2nd Quartile Median
• 3rd Quartile Median of upper half

15
Find the Median of the following

• 310, 320, 340, 340, 420, 430, 450, 460, 490, 630,
  640, 640, 670, 680, 950

• Median
• Median of lower half
• Median of upper half

16
Box Whisker Plots
950
310
460
640
340

• 1st Quartile 340
• 2nd Quartile 460
• 3rd Quartile 640

17
Box Whisker Plots
950
310
460
640
340

• Consider 460, find the percentage of numbers
  lower than 460.
• 50

18
Stem and Leaf Plot

• The Stem is the Tens digit
• The Leaf is the Ones digit
• Stem Leaf

19
Stem and Leaf Plot

• 310, 320, 340, 340, 420, 430, 450, 460, 490, 630,
  640, 640, 670, 680, 950

• Construct a Stem Leaf Plot with the above data.

20
Stem and Leaf Plot

• 9 5
• 6 8 7 4 4 3
• 4 9 6 5 3 2
• 3 4 4 2 1
• Key 9 5 950