| Flap 1 | Flap 2 |
| percentile rank | the percentage of scores in a distribution that fall below a given score |
| mode | the most frequently occuring score in the distribution |
| mean | arithmetic average |
| median | the middle score |
| range | the diference between the highest and lowest scores in a distribution |
| standard deviation | the measure of score variability; computed by calculating the deviation of each score from the mean, squared it, finding the average and the square root of that |
| normal curve | bell shaped distribution |
| regression toward the mean | the tendency for extremes of unusuall scores to fall back toward the average |
| statistical significnance | a statistictical statement abotu how liekly it is that a result occured by chance |
