Standard deviation measure how consist a set of data is. The smaller the standard deviation the more consistent the data is.

### How to Calculate Standard Deviation in a Graphing Calculator

### Example of Standard Deviation

Consider, for example, two sets of test scores. Class A's scores and class B's scores on a test on statistics. Below is a table showing both of the sets of scores

Class A's Scores | Class B 's Scores |
---|---|

80, 80, 80, 80, 80 | 20, 100, 20, 100 |

Both class A and class B have exactly the same arithmetic mean but clearly the mean of these scores does not represent who much each individual score deviates from this average of 80. **Enter** standard deviation. Standard deviation is the most common measure of how much individual scores vary from the actual mean. Class A has a standard deviation of 0. Class B, on the hand, has a much larger standard deviation.