For the test statistic value: STATS_F_TEST(expr1, expr2, 'STATISTIC') : STATS_F_TEST « Linear Regression Functions « Oracle PL/SQL Tutorial






This function tests the equality of two population variances.

The resulting f value is the ratio of one sample variance to the other sample variance.

Values very different from 1 usually indicate significant differences between the two variances.

SQL> -- create demo table
SQL> create table myTable(
  2    id           NUMBER(2),
  3    value        NUMBER(6,2)
  4  )
  5  /

Table created.

SQL>
SQL> -- prepare data
SQL> insert into myTable(ID,  value)values (1,9);

1 row created.

SQL> insert into myTable(ID,  value)values (2,2.11);

1 row created.

SQL> insert into myTable(ID,  value)values (3,3.44);

1 row created.

SQL> insert into myTable(ID,  value)values (4,-4.21);

1 row created.

SQL> insert into myTable(ID,  value)values (5,10);

1 row created.

SQL> insert into myTable(ID,  value)values (6,3);

1 row created.

SQL> insert into myTable(ID,  value)values (7,-5.88);

1 row created.

SQL> insert into myTable(ID,  value)values (8,123.45);

1 row created.

SQL> insert into myTable(ID,  value)values (9,98.23);

1 row created.

SQL> insert into myTable(ID,  value)values (10,938.23);

1 row created.

SQL> insert into myTable(ID,  value)values (11,984.23);

1 row created.

SQL> insert into myTable(ID,  value)values (12,198.23);

1 row created.

SQL> insert into myTable(ID,  value)values (13,928.87);

1 row created.

SQL> insert into myTable(ID,  value)values (14,25.37);

1 row created.

SQL> insert into myTable(ID,  value)values (15,918.3);

1 row created.

SQL> insert into myTable(ID,  value)values (16,9.23);

1 row created.

SQL> insert into myTable(ID,  value)values (17,8.23);

1 row created.

SQL>
SQL> select * from myTable
  2  /

        ID      VALUE
---------- ----------
         1          9
         2       2.11
         3       3.44
         4      -4.21
         5         10
         6          3
         7      -5.88
         8     123.45
         9      98.23
        10     938.23
        11     984.23

        ID      VALUE
---------- ----------
        12     198.23
        13     928.87
        14      25.37
        15      918.3
        16       9.23
        17       8.23

17 rows selected.

SQL>
SQL>
SQL> SELECT STATS_F_TEST(1.2, value, 'STATISTIC') FROM myTable;

STATS_F_TEST(1.2,VALUE,'STATISTIC')
-----------------------------------


SQL>
SQL>
SQL> -- clean the table
SQL> drop table myTable
  2  /

Table dropped.








20.12.STATS_F_TEST
20.12.1.For the test statistic value: STATS_F_TEST(expr1, expr2, 'STATISTIC')
20.12.2.For degrees of freedom: STATS_F_TEST(expr1, expr2, 'DF_NUM')
20.12.3.STATS_F_TEST(expr1, expr2, 'DF_DEN')
20.12.4.For significance level of one-sided test: STATS_F_TEST(expr1, expr2, 'ONE_SIDED_SIG')
20.12.5.For significance level of two-sided test: STATS_F_TEST(expr1, expr2, 'TWO_SIDED_SIG')