The INTERVALS statement tabulates various statistical intervals for selected process variables. The types of intervals you can request include

• approximate simultaneous prediction intervals for future observations

• prediction intervals for the mean of future observations

• approximate statistical tolerance intervals that contain at least a specified proportion of the population

• confidence intervals for the population mean

• prediction intervals for the standard deviation of future observations

• confidence intervals for the population standard deviation

These intervals are computed assuming the data are sampled from a normal population. See Hahn and Meeker (1991) for a detailed discussion of these intervals.

You can use options in the INTERVALS statement to

• specify which intervals to compute

• provide probability or confidence levels for intervals

• suppress printing of output tables

• create an output data set containing interval information

• specify interval type (one-sided lower, one-sided upper, or two-sided)