Introduction to Statistics
Graphic Displays
Pie charts and bar charts are graphic displays of data for categorical variables. Dot plots, stem-and-leaf plots, histograms, and box-and-whisker plots are graphic displays of data for numerical variables.
As an example, consider the yearly expenditures of a college undergraduate. After collecting her data (expense records) for the past year, she finds the expenditures shown in Table 1.
|
Item |
Amount |
|---|---|
|
Tuition fees |
$5,000 |
|
Room and board |
$9,000 |
|
Books and lab |
$2,000 |
|
Clothes/cleaning |
$1,000 |
|
Transportation |
$2,000 |
|
Insurance and miscellaneous |
$1,000 |
These figures, although presented in categories, do not allow for easy analysis. The reader must expend extra effort in order to compare amounts spent or relate individual proportions to the total. For ease of analysis, these data can be presented pictorially.
