Psych Stats Ch.3 Frequency Distribution and Percentiles

Relative Frequency

The proportion of the times the score occurs

symbol: rel. f

Tells you how each number relates to the whole set of numbers

Normal Distribution

• Bell-shaped curve

• Called the normal curve or a normal distribution

• symmetrical

• the far left and far right portions containing the low frequency extreme scores are called the tails of distribution

Positively Skewed Distribution

Simple Frequency Bar Graph

• Used for nominal and ordinal data

• space between the bars show discrete measures

Rectangular Distribution

Symmetrical distribution shaped like a rectangle

Bimodal Distribution

A symmetrical distribution containing two distinct humps

Skewed Distributions

• not symmetrical as it only has on pronounced tail

• a distribution may be either negatively or positively skewed

Histogram

Used for a small range of different interval or ratio scores

A Frequency Polygon

• Used for a large number of different scores