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.