Stat Vocab 2

A frequency table lists the categorical variable and gives the count of observations for each category.

A frequency table lists the categorical variable and gives the percentage of observations for each category.

• The distribution of a variable gives
• -- the possible values of the variable and
• -- the relative frequency of each value

In a statisical display, each data value should be represented by the same amount of area

Bar charts show a bar repesenting the count of each category in a categorical variable.

Pie charts show how a "whole" divides into categories by showing a wedge of a circle whose area corresponds to the proportion in each category.

A contingency table displays counts and, somtimes, percentages of individuals falling into named categories on two or more variables. The table categorizes the individuals on all variables at once, to reveal possible patterns in one variable that may be contingent on the category of the other.

In a contigency table, the distribution of either variable alone is called the marginal distribution. The counts or percentages are the totals found in the margins (last row or column) of the table.

The distribution of a variable restricting the Who to consider only a smaller group of individuals is called a conditional distribution.

Variables are said to be independent if the conditional distribution of one variable is the same for each category of the other.

When averages are taken across different groups, they can appear to contradict the overall averages.