PROBT Function

Returns the probability from a t distribution of the values in an expression.

Categories: Aggregate
Descriptive Statistics
Returned data type: DOUBLE
Syntax
Arguments
Details
Comparisons
Example
See Also

Syntax

PROBT(expression)

Arguments

expression

specifies any valid SQL expression.

Data type DOUBLE
See <sql-expression>
FedSQL Expressions

Details

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.

Comparisons

The STUDENTS_T function returns the Student's t-distribution. The PROBT function returns the probability that the Student's t-distribution is less than or equal to a given value.

Example

Table: DENSITIES
The following statements illustrate the PROBT function:
Statements
Results
 
select probt(density) from densities;
 
0.006068
 
select probt(population) from densities;
 
0.009722

See Also

Functions:
STUDENTS_T Function
SELECT Statement Clauses:
SELECT Clause
GROUP BY Clause
HAVING Clause
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Last updated: February 23, 2017