The FREQ statement specifies a variable that provides frequency counts for each observation in the input data set. If is the value of the FREQ variable for an observation, then that observation is weighted by . The log-likelihood function for maximum likelihood estimation is multiplied by . If is not an integer, the integer part of is used in creating probability plots.

You can also use the FREQ statement in conjunction with the NENTER statement to specify interval-censored data having a special structure; these data are called readout data. The FREQ statement specifies a variable in the input data set that determines the number of units failing in each interval. See the section Weibull Analysis of Interval Data with Common Inspection Schedule for an example that uses the FREQ statement with readout data.

You can use the FREQ statement with the MCFPLOT statement for exact age data to provide frequency counts for entire recurrence histories. If is the value of the FREQ variable at a censor time, the history of recurrences for the corresponding system is replicated independently times. Values of the FREQ variable at times other than censor times are not used, and may be any value or missing without affecting the analysis. The FREQ variable is not used with the MCFPLOT statement for interval recurrence data, and the values of a FREQ variable specified in this case are ignored.