The T_ME_TEST stored procedure calculates the t-Student statistics of a numeric input
column to evaluate the significance of the difference between the sample mean value and an expected
mean value.
Syntax
IDAX.T_ME_TEST(in parameter_string varchar(32672))
Parameter descriptions
- parameter_string
- Mandatory one-string parameter that contains pairs of
<parameter>=<value> entries that are separated by a comma.
- Data type: VARCHAR(32672)
- The following list shows the parameter values:
-
- intable
- Mandatory.
- The name of the input table.
- Data type: VARCHAR(256)
- incolumn
- Mandatory.
- The numeric column of the input table.
- Data type: VARCHAR(128)
- mean
- Mandatory.
- The expected mean value of the input column.
- Data type: DOUBLE
- by
- Optional.
- The column of the input table that splits the data into groups for which the stored procedure is
to be executed.
- Default: none
- Data type: VARCHAR(128)
- outtable
- Mandatory.
- The name of the output table to which the t-Student statistics are written.
- The output table contains the T_ME_TEST column and the PERCENTAGE column.
- If the by parameter is specified, an extra BY column is added to indicate
for which group the t-Student statistics are calculated.
- The T_ME_TEST column contains a string with the t-Student value and the degree of freedom.
- The PERCENTAGE column indicates the probability that the column has the expected mean value:
- If the percentage ranges from 0 to 0.05, the mean value is too high.
- If the percentage ranges between 0.05 and 0.95, the expected mean value matches the mean value
of the column.
- If the percentage ranges between 0.95 and 1, the expected mean value is too low.
- Data type: VARCHAR(256)
Returned information
DOUBLE the probability that the column of the input table has the expected mean value, or the
number of groups in the output table for which t-Student statistics are calculated.
Example
CALL IDAX.T_ME_TEST('intable=IRIS, incolumn=petallength, mean=3.76, outtable=ME_TEST_RESULT1');
CALL IDAX.T_ME_TEST('intable=IRIS, incolumn=petallength, mean=3.76, by=class, outtable=ME_TEST_RESULT2');