1. Measures of Central Tendency

2. Measures of Central Tendency
DEF: Those measurements that indicate the central values of a data set (the averages) How many are there? 3 What are they called? Mean – Median - Mode

3. Definitions of the three measures of central tendency
Mean
The value resulting from adding all the numbers up in a data set, and dividing by the number of values in the data set.
Median
The central number in a data set that has been placed in chronological order. A mean average of both central values is taken when the sample has an equal number of values.
Mode
The most common occurring number in a data set

4. Measures of Central Tendency
How do you work out the mean?
One adds up all the values in the data set and divides by the number of values
What is the mean for this data set?
583/ 7 = 83.2

5. Measures of Central Tendency
What is the median of this data set
The median is 16+17/2 = 16.5
What is the mode of this data set
The mode is 16

6. Measures of Central Tendency
Draw a grid and fill it in using the information below:
Decide which are advantages and disadvantages of each measure of central tendency (see next slide for answers)
Very large or very small numbers (anomalies) can distort the answer
All the data are used in it’s calculation, making it a powerful measure
It must be a number that appears in the data set
Is not affected by very large or very small numbers
Maybe more than one value, or no value exists.
Does not use the actual mathematic data, only the position of the number in the series
Advantages
Disadvantages
Mean
Median
Mode

7. Measures of Central Tendency
Advantages
Disadvantages
Mean
All the data are used in it’s calculation, making it a powerful measure
Very large or very small numbers (anomalies) can distort the answer
Median
Is not affected by very large or very small number
Does not use the actual mathematic data, only the position of the number in the series
Mode
It must be a number that appears in the data set
Maybe more than one value, or no value exists.