The normal distribution is a theoretical distribution but it allows us to make descriptive statements about a raw scores that are randomly sampled from empirical distributions that may be assumed normal.
| The difference between theoretical and empirical distributions confuses you? Click here to compare the two. |
Take Thomson Higher Education's workshop on z-scores.
The normal curve table allows us to determine the total area 1) above or below a score and 2)between two scores. Click HERE to view David Lane's interactive calculators for the normal distribution.
Depending on the what is required by a normal curve problem, the area under the normal curve may be expressed as
- proportion of cases/respondents
- percentage of cases when multiplied by 100
- number of respondents when multiplied by N (sample size).
Moreover, the area may also be expressed as probabilities. This is particularly important because when doing inferential statistics (and that's what we will do for the entire semester) we will be concerning ourselves with determining the probabilities of the occurrence of certain events.
Below is a ppt presentation from the publishers of our book:
Click HERE if you wish to view the downloadable handout with notes.
Review the lesson using the the following materials from Wadsworth Cengage:
Take Self Tests 05, 06 and 07.
