By default, each observation is
counted only once in the calculation of the chart statistics. To
calculate weighted statistics in which an observation can be counted
more than once, use the FREQ= option. This option identifies a variable
whose values are used as a multiplier for the observation in the calculation
of the statistic. If the value of the FREQ= variable is missing,
0, or negative, the observation is excluded from the calculation.

If you use the SUMVAR=
option, then for each observation, the value of the SUMVAR= variable
is multiplied by the value of the FREQ= variable in calculating the
chart statistic.