SAS PROBT Function: Returns the probability from a t distribution of the values in an expression. The PROBT function returns the probability that an observation from a Student’s t distribution, with degrees of freedom n-1 and noncentrality parameter nc equal to 0, is less than or equal to expression. The significance level of a two-tailed t test is given by this code line. p=(1-probt(abs(x),df))*2; You can use an aggregate function to produce a statistical summary of data in the entire table that is listed in the FROM clause or for each group that is specified in a GROUP BY clause. The GROUP BY clause groups data by a specified column or columns. When you use a GROUP BY clause, the aggregate function in the SELECT clause or in a HAVING clause instructs FedSQL in how to summarize the data for each group. FedSQL calculates the aggregate function separately for each group. If GROUP BY is omitted, then all the rows in the table or view are considered to be a single group.