SECTION 15.17 TESTING FOR THE DIFFERENCE BETWEEN MEANS

This tests whether the means from two samples are different. The test is asymptotically valid if the underlying distributions have finite first two moments; the test statistic is approximately t- distributed. The MAIN program should include

        COMMON/BPRINT/IPT,NFILE,NDIG,NPUNCH,JPT,MFILE
        CALL DFLT

The call is

        CALL TESTMEAN(A1,A2,N1,N2,TVAL)

where

        A1   = a DOUBLE PRECISION array dimensioned A1(N1) which
               contains the values of the first sample (input)
        A2   = a DOUBLE PRECISION array dimensioned A2(N2) which
               contains the values of the first sample (input)
        N1,N2= sizes of the two samples (input)
        TVAL = DOUBLE PRECISION scalar which will contain the
               calculated t-value (output)

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