### inferential statistics

procedures used to analyze data after an experiment is completed in order to determine whether the IV had a significant effect

### nominal scale

a scale in which the events are assigned to categories (i.e. left-handed vs right-handed)

### ordinal scale

a scale that permits events to be rank ordered without necessarily having equal distance between points

### interval scale

a scale that permits rank ordering with the assumption of equal intervals between adjacent events (no true zero)

### ratio scale

a scale of measurement that permits rank ordering, equal distance, and a true zero point

### pie chart

graphical representation of the percentage allocated to each alternative as a slice of a circular pie

### histogram

A graph of vertical bars representing the frequency distribution of a set of data, the bars touch, generally intervals

### bar graph

a graph in which the frequency of each category of a qualitative variable is represented as a vertical column, bars do not touch.

### frequency polygon

type of line graph that shows frequency distributions; made by placing a dot on each bar of a histogram, connecting the dots, and removing the bars

### range

a measure of variability that is computed by subtracting the smallest score from the largest score

### variance

a single number that represents the total amount of variation in a distribution, also the square of the standard deviation

### normal distribution

a symmetrical, bell-shaped distribution having half the scores above the mean and half the scores below the mean (bell curve)

### null hypothesis

the claim that the relationship proposed between two variables does not exist, or that the difference in data was due to chance (not the operation of the IV)