(6.4) Measuring the Spread of Data - Discrete Data
Variance and Standard Deviation
Variance and Standard deviation are also measures of the spread of data.Their calculations use all of the data values and how far they are from the mean.
For example,
Mean, $\mu$ =
| Data $x$ |
$5$ | $6$ | $6$ | $6$ | $6$ | $6$ | $7$ | $7$ | $7$ | $7$ | $7$ | $7$ | $7$ | $7$ | $7$ | $8$ | $8$ | $8$ | $8$ | $8$ | $9$ |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| $x-\mu$ | $-2$ |