Standard deviation:
ungrouped
data
Standard deviation:
grouped
data
Standard deviation
example:
scores on a midterm
Standard deviation:
calculating formula
Standard
deviations:
calculating formula
Standard deviation:
calculating
formula
| If the population is normally distributed, you can estimate the percentage of the population within 1, 2, and 3 standard deviations of the mean: | |
| 68% of cases lie +/- 1 s.d. of mean | |
| 95% of cases lie +/- 2 s.d.’s of mean | |
| 99.9% of cases lie +/- 3 s.d.’s of mean |