AP Psych - Standard Deviation Quiz

Alpha Level

Sets the standard for how extreme the data must be before we can reject the null hypothesis. Typically .05. Meaning we will accept 5% chance of error, or a 95% confidence results are not due to chance.

Variance

A statistical average of the amount of dispersion around the mean in a distribution of the scores. It is the Standard Deviation squared.

Standard Deviation

A statistical measure of the amount of dispersion in a set of scores. Specifically it is the square root of the average squared deviations from the mean of a set of scores. It is simply the square root of the variance.

Mean

Arithmetical average calculated by dividing a sum of values by the total number of cases. Most affected by outliers or extreme scores.

Range

Difference between the largest and smallest scores in a distribution. Most affected by outliers.

Median

Point that divides a set of scores in half.

Mode

The most frequent score in a distribution of scores.

Statistical Significance

Using statistical analysis, the probability that the results obtained were due to chance (represented by p-value). In psychology it is standard that a p-value of .05 or less means that results were statistically significant (i.e. not due to chance)