Basic Analysis and Graphing - SAS

318 Creating Summary Charts Chapter 11
Example of the Chart Platform
Mean
Variance
Std Dev
Std Err
CV
Range
Median
Quantiles
The arithmetic average of a column’s values. The mean is the sum of nonmissing values
divided by the number of nonmissing values.
The sample variance computed for each level of a categorical variable.
The sample standard deviation computed for each level of a categorical variable. It is the
square root of the variance of the level values.
The standard error of the mean of each level of a categorical variable. It is the standard
deviation, Std Dev, divided by the square root of N for each level. If a column is assigned a
weight variable, then the denominator is the square root of the sum of the weights.
The coefficient of variation of a column’s values. The CV is computed by dividing the
column standard deviation by the column mean and multiplying by 100.
The difference between the maximum and minimum values in each level of a categorical
variable.
The middle value in each level of a categorical variable. Half of the values in the level are
greater than or equal to the median and half are less than the median.
Divides a data set so that n% of the data is below the n th quantile. To compute a specific
quantile, enter the quantile value in the box located in the lower left of the Chart launch
window before requesting Quantile from the menu.
Related Information
• “Plot a Single Statistic” on page 326
• “Plot Multiple Statistics” on page 327
Use Categorical Variables
You can assign zero, one, or two X variables whose levels are categories on the x-axis. The Chart platform
produces a bar (or a needle, or a pie slice, and so on) for each level or combination of levels of the X
variables. If you do not specify any X variable, the chart has a bar for each row in the data table.
The following table shows what type of chart to expect based on the number of X and Y variables.
X Y Type of Chart
none one or more If you do not specify a variable for categories, most statistics produce a bar
(or a needle, or a pie slice, and so on) for each observation in the data table.
This is useful when your data is already summarized. In that case, you
usually specify Data as the statistic to plot. Each bar reflects the value of
the Y variable. See “Plot a Single Statistic” on page 326, for an example.