MD_TEST

The MD_TEST function tests the hypothesis that a sample population is random against the hypothesis that it is not random. The result is a two-element vector containing the nearly-normal test statistic Z and its associated probability. This two-tailed is an extension of the "Runs Test for Randomness" and is often referred to as the Median Delta Test.

This routine is written in the IDL language. Its source code can be found in the file md_test.pro in the lib subdirectory of the IDL distribution.

Calling Sequence

Result = MD_TEST( X )

Arguments

X

An n -element integer, single- or double-precision floating-point vector.

Keywords

ABOVE

Use this keyword to specify a named variable that will contain the number of sample population values greater than the median of X .

BELOW

Use this keyword to specify a named variable that will contain the number of sample population values less than the median of X .

MDC

Use this keyword to specify a named variable that will contain the number of Median Delta Clusters (sequential values of X above and below the median).

Example

Define a sample population.

X = [ 2.00,  0.90, -1.44, -0.88, -0.24,  0.83, -0.84, -0.74, $

      0.99, -0.82, -0.59, -1.88, -1.96,  0.77, -1.89, -0.56, $

     -0.62, -0.36, -1.01, -1.36]

Test the hypothesis that X represents a random population against the hypothesis that it does not represent a random population at the 0.05 significance level.

result = MD_TEST(X, MDC = mdc)

PRINT, result

IDL prints:

0.459468    0.322949

The computed probability (0.322949) is greater than the 0.05 significance level and therefore we do not reject the hypothesis that X represents a random population.

See Also

CTI_TEST , FV_TEST , , , R_TEST , RS_TEST , S_TEST , TM_TEST , XSQ_TEST