The UNIVARIATE Procedure

# Results

By default, PROC UNIVARIATE produces tables of moments, basic statistical measures, tests for location, quantiles, and extreme observations. You must specify options in the PROC UNIVARIATE statement to produce other statistics and tables.

The CIBASIC option produces the table of the basic confidence measures that includes the confidence limits for the mean, standard deviation, and variance. The CIPCTLDF option and CIPCTLNORMAL option produce tables of confidence limits for the quantiles. The LOCCOUNT option produces the table that shows the number of values greater than, equal to, and less than the value of MU0=. The FREQ option produces the table of frequencies counts. The NEXTRVAL= option produces the table with the frequencies of the extreme values. The NORMAL option produces the table with the tests for normality. The TRIMMED=, WINSORIZED=, and ROBUSTCALE options produce tables with robust estimators.

The table of trimmed or Winsorized means includes the percentage and the number of observations that are trimmed or Winsorized at each end, the mean and standard error, confidence limits, and the Student's t test. The table with robust measures of scale includes interquartile range, Gini's mean difference G, MAD, , and , with their corresponding estimates of .

PROC UNIVARIATE excludes missing values for the analysis variable before calculating statistics. Each analysis variable is treated individually; a missing value for an observation in one variable does not affect the calculations for other variables. The statements handle missing values as follows:

• If a BY or an ID variable value is missing, PROC UNIVARIATE treats it like any other BY or ID variable value. The missing values form a separate BY group.

• If the FREQ variable value is missing or nonpositive, PROC UNIVARIATE excludes the observation from the analysis.

• If the WEIGHT variable value is missing, PROC UNIVARIATE excludes the observation from the analysis.

PROC UNIVARIATE tabulates the number of the missing values and reports this information in the procedure output. Before the number of missing values is tabulated, PROC UNIVARIATE excludes observations when

• you use the FREQ statement and the frequencies are nonpositive

• you use the WEIGHT statement and the weights are missing or nonpositive (you must specify the EXCLNPWGT option).

If you request a fitted parametric distribution with a HISTOGRAM statement, PROC UNIVARIATE creates a report that summarizes the fit in addition to the graphical display. The report includes information about

• parameters for the fitted curve, estimated mean, and estimated standard deviation

• EDF goodness-of-fit tests

• histogram intervals

• quantiles.

### Histogram Intervals

If you specify the MIDPERCENTS suboption in parentheses after a density estimate option, PROC UNIVARIATE includes a table that lists the interval midpoints along with the observed and estimated percentages of the observations that lie in the interval. The estimated percentages are based on the fitted distribution. You can also specify the MIDPERCENTS suboption to request a table of interval midpoints with the observed percentage of observations that lie in the interval.

### Quantiles

By default, PROC UNIVARIATE displays a table that lists observed and estimated quantiles for the 1, 5, 10, 25, 50, 75, 90, 95, and 99 percent of a fitted parametric distribution. You can use the PERCENTS= suboption to request that the quantiles for specfic percentiles appear in the table.

PROC UNIVARIATE can create one or more output SAS data sets. When you specify an OUTPUT statement and no BY statement, PROC UNIVARIATE creates an output data set that contains one observation. If you use a BY statement, the corresponding output data set contains an observation with statistics for each BY group. The procedure does not print the output data set. Use PROC PRINT, PROC REPORT, or another SAS reporting tool to print the output data set.

The output data set includes

• BY statement variables

• variables that contain statistics

• variables that contain percentiles.

The BY variables indicate which BY group each observation summarizes. When you omit a BY statement, the procedure computes statistics and percentiles by using all the observations in the input data set. When you use a BY statement, the procedure computes statistics and percentiles by using the observations within each BY group.

You can create a OUTHISTOGRAM= data in the HISTOGRAM statement that contains information about histogram intervals. Because you can specify multiple HISTOGRAM statements with the UNIVARIATE procedure, you can create multiple OUTHISTOGRAM= data sets.

The data set contains a group of observations for each variable that the HISTOGRAM statement plots. The group contains an observation for each interval of the histogram, beginning with the leftmost interval that contains a value of the variable and ending with the rightmost interval that contains a value of the variable. These intervals will not necessarily coincide with the intervals displayed in the histogram since the histogram may be padded with empty intervals at either end. If you superimpose one or more fitted curves on the histogram, the OUTHISTOGRAM= data set contains multiple groups of observations for each variable (one group for each curve). If you use a BY statement, the OUTHISTOGRAM= data set contains groups of observations for each BY group. ID variables are not saved in the OUTHISTOGRAM= data set.

The variables in OUTHISTOGRAM= data set are
 _CURVE_ name of fitted distribution (if requested in HISTOGRAM statement) _EXPPCT_ estimated percent of population in histogram interval determined from optional fitted distribution _MIDPT_ midpoint of fitted distribution _OBSPCT_ percent of variable values in histogram interval _VAR_ variable name