Ch. 2

histogram

A common graphical presentation of quantitative data, no natural separation between rectangles

frequency distribution

A summary chart, showing how frequently each of the various scores in a set of data occurs

contingency table

A table used to classify sample observations according to two or more identifiable categories or classes.

frequency

How often a piece of data occurs.

relative frequency

Number of times an allele occurs in a gene pool compared with the number of times other alleles occur

ogive

a graph of the cumulative relative frequencies from a relative frequency distribution

values of a variable

a set of ranges within which the data fall

stem and leaf diagram

a simple way to see distribution details quantitative data

cell

gives the count for a combination of values of the two variables

cumulative relative frequencies

cumulative frequency of a class divided by the total number of observations

bar chart

displays the distribution of a categorical variable, showing the counts for each category next to each other for easy comparison

relative frequency table

displays the percentages that lie in each category rather than the counts

corresponding frequencies

frequencies with which data fall within each range

pie chart

is a commonly used graphical device for presenting relative frequency distributions for qualitative data

bar graph

is a graphical device for depicting qualitative data

frequency table

is a tabular summary of data showing the frequency of items in each of several non-overlapping classes

percent frequency

is the relative frequency multiplied by 100. distribution

continuous data

may take on any value in some interval

conditional distribution

restrict variables in a distribution to show the distribution for just those cases that satisfy a specified condition

relative frequency bar chart

shows a bar representing the percentage count of each category in a categorical variable

bars are separated

technique used to distance bars on graph

categorical data condition

the data are counts or percentages of individuals in categories

column percent

the proportion of each column contained in the cell of a frequency table

row percent

the proportion of each row contained in the cell of a frequency table

total percent

the proportion of the total contained in the cell of a frequency table

marginal distribution

the total count that occurs when the value of that variable is held constant

bar of fixed with

used to create bars on bar graph