Equal Variance Test

hanaml.ftest.equal.var is a R wrapper for SAP HANA PAL Equal Variance Test.

hanaml.ftest.equal.var(data.x, data.y, test.type = NULL)

Arguments

data.x	DataFrame DataFrame containting the attribute data.
data.y	DataFrame DataFrame containting the attribute data.
test.type	{'two.sides', 'less','greater'}, optional States the type of the alternative hypothesis for the F test. The types are given as follows: 'two.sides': The variances are not equal 'less':variance from the first population is less than the second population variance 'greater':variance from the first population is greater than the second population variance Defaults to 'two.sides'.

Value

DataFrame
Statistics, structured as follows:

• STAT_NAME Name of statistics

• STAT_VALUE Value of statistics

Details

This function uses statistical F Test to compare two variances s1 and s2 of two samples by dividing them, i.e. F = s1^2 / s2^2.

Examples

Two input Dataframe:

 > df.x$Collect()
    X
 1  1
 2  2
 3  4
 4  7
 5  3

> df.y$Collect()
      Y
1  10.0
2  15.0
3  12.0

Call the function:

> res <- hanaml.ftest.equal.var(data.x, data.y, test.type="two.sides")

Results:

> res$Collect()

                       STAT_NAME  STAT_VALUE
1                        F Value    0.836842
2    numerator degree of freedom    4.000000
3  denominator degree of freedom    2.000000
4                        p-value    0.783713