The T_LS_TEST stored procedure calculates the t-Student statistics of two numeric input
columns to evaluate the significance of the linear relationship between them. It measures whether
the column has the given mean.
Syntax
IDAX.T_LS_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 two numeric columns of the input table that are separated by a semi-colon (;).
- One column must be followed by :X, the other column by :Y.
- Data type: VARCHAR(ANY)
- slope
- Mandatory.
- The expected direction of dependence Y=X*slope+constant.
- Data type: DOUBLE
- by
- Optional.
- The column of the input table that splits the data into groups for which the t-Student
statistics are calculated.
- 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_LS_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_LS_TEST column contains a string with the t-Student value, the degree of freedom, the
variance, and the linear coefficients that relate to both columns.
- The PERCENTAGE column indicates the probability of the dependence of the two columns as follows:
- If the percentage ranges from 0 to 0.05, the slope is too high.
- If the percentage ranges between 0.05 and 0.95, the indicated slope is acceptable. The smaller
the percentage is, the more independent the columns are.
- If the percentage ranges between 0.95 and 1, the slope is too low.
- Data type: VARCHAR(256)
Returned information
DOUBLE the probability of the dependence of the two columns of the input table, or the number of
groups in the output table for which t-Student statistics are calculated.
Example
CALL IDAX.T_LS_TEST('intable=IRIS,incolumn=petallength:X;sepallength:Y, slope=1.5,outtable=LS_TEST_RESULT1');
CALL IDAX.T_LS_TEST('intable=IRIS,incolumn=petallength:X;sepallength:Y, slope=1.5,by=class, outtable=LS_TEST_RESULT2');