1. 9.2 - Measures of Central Tendency
Objective: TSW calculate the measures of central tendency for a set of data.
© 2008 Pearson Addison-Wesley. All rights reserved

2. Measures of Central Tendency – “middle type number”
Mean – the average also known as arithmetic mean. The mean of a sample is denoted (read “x bar”), while the mean of a complete population is denoted (the lower case Greek letter mu).
The sum of…
© 2008 Pearson Addison-Wesley. All rights reserved

3. © 2008 Pearson Addison-Wesley. All rights reserved
Median – the middle number. This measure divides a group of numbers into two parts, with half the numbers below the median and half above it. Mode – most repeated number. Bimodal – two modes.
© 2008 Pearson Addison-Wesley. All rights reserved

4. Example: Find the mean, median and mode for the following data.
Ten students in a math class were polled as to the number of siblings in their individual families and the results were: 3, 2, 2, 1, 3, 6, 3, 3, 4, 2.
Find the mode for the number of siblings.
© 2008 Pearson Addison-Wesley. All rights reserved

5. Examples of Symmetry in Data Sets
© 2008 Pearson Addison-Wesley. All rights reserved

6. Non-symmetric Distributions – skewed left or skewed right.
© 2008 Pearson Addison-Wesley. All rights reserved

7. © 2008 Pearson Addison-Wesley. All rights reserved
Homework
Worksheet
© 2008 Pearson Addison-Wesley. All rights reserved