The UNIVARIATE Procedure
Rounding
When you specify ROUND=u, PROC UNIVARIATE rounds a variable by using the rounding unit to divide the number line into intervals with midpoints of the form 
, where u is the nonnegative rounding unit and i is an integer. The interval width is u. Any variable value that falls in an interval is rounded to the midpoint of that interval. A variable value that is midway between two midpoints, and is therefore on the boundary of two intervals, rounds to the even midpoint. Even midpoints occur when i is an even integer 
.
When ROUND=1 and the analysis variable values are between –2.5 and 2.5, the intervals are as in Table 26.
Table 26: Intervals for Rounding When ROUND=1
| i | Interval | Midpoint | Left endpoint rounds to | Right endpoint rounds to |
|---|---|---|---|---|
| –2 | [–2.5, –1.5] | –2 | –2 | –2 |
| –1 | [–1.5, –0.5] | –1 | –2 | 0 |
| 0 | [–0.5, 0.5] | 0 | 0 | 0 |
| 1 | [0.5, 1.5] | 1 | 0 | 2 |
| 2 | [1.5, 2.5] | 2 | 2 | 2 |
When ROUND=0.5 and the analysis variable values are between –1.25 and 1.25, the intervals are as in Table 27.
Table 27: Intervals for Rounding When ROUND=0.5
| i | Interval | Midpoint | Left endpoint rounds to | Right endpoint rounds to |
|---|---|---|---|---|
| –2 | [–1.25, –0.75] | –1.0 | –1 | –1 |
| –1 | [–0.75, –0.25] | –0.5 | –1 | 0 |
| 0 | [–0.25, 0.25] | 0.0 | 0 | 0 |
| 1 | [0.25, 0.75] | 0.5 | 0 | 1 |
| 2 | [0.75, 1.25] | 1.0 | 1 | 1 |
As the rounding unit increases, the interval width also increases. This reduces the number of unique values and decreases the amount of memory that PROC UNIVARIATE needs.