These are measures of central tendency any set of quantities may be represented by one of its averages.
This is the difference between the highest and lowest value.
- The Arithmetic mean.
This is obtained by diving the sum of the quantities by the number of quantities.
- If the marks obtained by 10 students in a history test out of 10 are 8,4,6,2,5,6,5,7,9,7
Large quantities are handeled in the frequency table
- Organize the information in a frequency table.
The modal are 5o and 52
Modal frequency is 6
- Calculate the mean.
Finding the Arithmetic mean using the assumed mean method.
An assumed mean is obtained by inspection used to find the arithmetic mean as follow;
Given the figures below.
Taking the assumed mean as
For easier handling of large frequencies we use the frequency tables in the next examples.
Below are heights in cm of 30 students in 52m
This is the number in the middle , when the items are written in increasing (ascending) or decreasing order.
Find the median in each of the following cases
Medians 4 it was the fifth.
Height in cm of 10 girls; 160, 165, 162, 166, 167, 162, 164, 161, 162, 163.
160, 161, 162, 163, 164, 165, 166, 107