Overview: INTERVALS Statement

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)