## STATS_WSR_TEST

**Syntax**
**stats_wsr_test::=**
Description of the illustration stats_wsr_test.gif
**Purpose**
`STATS_WSR_TEST`

is a Wilcoxon Signed Ranks test of paired samples to determine whether the median of the differences between the samples is significantly different from zero. The absolute values of the differences are ordered and assigned ranks. Then the null hypothesis states that the sum of the ranks of the positive differences is equal to the sum of the ranks of the negative differences.

This function takes three arguments: `expr1`

and `expr2`

are the two samples being analyzed, and the third argument is a return value of type `VARCHAR2`

. If you omit the third argument, the default is `TWO_SIDED_SIG`

. The meaning of the return values is shown in Table 7-10.