Graphical Displays of Data

Exam 1

Bar Graph

A graphical display of data where the length of each bar corresponds to the number or percentage of observation in a category or group

• Often done with qualitative data

• Bars do not touch

Rules of a bar graph

X-axis: Category

Y-axis: # of responses

Frequency Distribution

A table that lists data and their coresponding frequencies (counts)

• Data can be listed individually (not done that often because of ungrouped frequency where information is not informative because there is not repetition) or grouped into classes

• Quantitative data

Rules of Frequency Distribution (tabular)

Left- make ranges that are called classes

• when you pick the range, you must stay with the pattern

• label in a way that represents all data ex. 20-29.99

Relative Frequency Distribution (tabular)

Represents the proportion of values falling in a given class interval

• proportions are decimal points

Formula:

#in a given class (count)/ total # of values

Histogram

A graphical representation of a frequency or relative frequency distribution

Rules of a Histogram

• y-axis: represents frequencies or relative frequencies

• x-axis: represents class intervals

• ** bars touch