PROC UNIVARIATE has provided confidence intervals for standard percentiles (quartiles) for eons. However, in SAS 9.3M2 (featuring the 12.1 analytical procedures) you can use a new feature in PROC UNIVARIATE to compute confidence intervals for a specified list of percentiles. To be clear, percentiles and quantiles are essentially the same thing. For example, the median value of a set of data is the 0.5 quantile, which is also the 50th percentile. In general, the pth quantile is the (100 p)th percentile.
The CIPCTLDF option on the PROC UNIVARIATE statement produces distribution-free confidence intervals for the 1st, 5th, 10th, 25th, 50th, 75th, 90th, 95th, and 99th percentiles as shown in the following example:
/* CI for standard percentiles: 1, 5, 10, 25, 50, 75, 90, 95, 99 */ ods select Quantiles; proc univariate data=Sashelp.Cars cipctldf; var MPG_City; run;
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