1. Measures of Central Tendency

2. The Big Three – Mean, Median & Mode Mean Most common measure Arithmetic average Statistical symbols PopulationSample μ Nn

3. Arithmetic Mean

4. Feb10 Mar9.5 Apr7.3 May4.8 Jun3

5. Median The middle value, when listed from smallest to largest. Half of data is above median, half below With even number of data values, median is half-way between the two central values 3 5 7 7 9 10 11 33 50Median = 9 3 5 7 9 10 11 33 50Median = 9.5

6. Mode ▫ Value that occurs with greatest frequency ▫ Unimodal  3 5 8 1 -7 2 5 ▫ Bimodal  3 5 -7 1 -7 2 5 ▫ Multi-modal  3 5 -7 1 -7 3 5 ▫ No mode  3 5 8 1 -7 2 5  Or  3 5 -7 -7 3 5

7. Practice Exercise Consider the following data: 4, -8, 4, -12, 8, 4, -14 What is the value of the mean?

8. Practice Exercise Consider the following data: 4, -8, 4, -12, 8, 4, -14 What is the range?

9. Practice Exercise Consider the following data: 4, -8, 4, -12, 8, 4, -14 What (if any) is the value of the mode(s)?

10. Practice Exercise Consider the following data: 4, -8, 4, -12, 8, 4, -14 What is the value of the median?