ch 2 - frequency distribution

frequency distribution

a distribution in which the scores (values) are plotted against their frequency or occurrence

histogram

a graph in which numerical data is represented with a rectangle that is used to represent frequencies/proportions of observations

bar graph

a graph in which the frequency of occurrence of different values of X is represented by the height of bar for categorical data

symmetric distribution

a distribution having the same shape on both sides of the center

positively-skewed distribution

distribution that trails off to the right

negatively-skewed distribution

distribution that trails off to the left

cumulative percentage

percentage of individuals who are at or below each score/interval on the scale; “reverse of a rank”

percentile rank

percentage of individuals in the distribution with scores equal to or less than a particular value

percentile score

score associated with a certain percentile rank

tail(s) of a distribution

section where the scores taper off toward one end of the distribution

3 characteristics to describe distributions

shape, central tendency, and variability