Standard deviation is the square root of the average of squared deviations of the items from their mean. Symbolically it is represented by σσ.
We’re going to discuss methods to compute the Standard deviation for three types of series:
· Individual Data Series
· Discrete Data Series
· Continuous Data Series
Individual Data Series
When data is given on individual basis. Following is an example of individual series:
| Items | 5 | 10 | 20 | 30 | 40 | 50 | 60 | 70 |
Discrete Data Series
When data is given alongwith their frequencies. Following is an example of discrete series:
| Items | 5 | 10 | 20 | 30 | 40 | 50 | 60 | 70 |
| Frequency | 2 | 5 | 1 | 3 | 12 | 0 | 5 | 7 |
Continuous Data Series
When data is given based on ranges alongwith their frequencies. Following is an example of continous series:
| Items | 0-5 | 5-10 | 10-20 | 20-30 | 30-40 |
| Frequency | 2 | 5 | 1 | 3 | 12 |
