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decus_20tap2_198111
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decus/20-0026/kolmo.doc
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SUBROUTINE KOLMO
PURPOSE
TESTS THE DIFFERENCE BETWEEN EMPIRICAL AND THEORETICAL
DISTRIBUTIONS USING THE KOLMOGOROV-SMIRNOV TEST
USAGE
CALL KOLMO(X,N,Z,PROB,IFCOD,U,S,IER)
DESCRIPTION OF PARAMETERS
X - INPUT VECTOR OF N INDEPENDENT OBSERVATIONS. ON
RETURN FROM KOLMO, X HAS BEEN SORTED INTO A
MONOTONIC NON-DECREASING SEQUENCE.
N - NUMBER OF OBSERVATIONS IN X
Z - OUTPUT VARIABLE CONTAINING THE GREATEST VALUE WITH
RESPECT TO X OF SQRT(N)*ABS(FN(X)-F(X)) WHERE
F(X) IS A THEORETICAL DISTRIBUTION FUNCTION AND
FN(X) AN EMPIRICAL DISTRIBUTION FUNCTION.
PROB - OUTPUT VARIABLE CONTAINING THE PROBABILITY OF
THE STATISTIC BEING GREATER THAN OR EQUAL TO Z IF
THE HYPOTHESIS THAT X IS FROM THE DENSITY UNDER
CONSIDERATION IS TRUE. E.G., PROB = 0.05 IMPLIES
THAT ONE CAN REJECT THE NULL HYPOTHESIS THAT THE SET
X IS FROM THE DENSITY UNDER CONSIDERATION WITH 5 PER
CENT PROBABILITY OF BEING INCORRECT. PROB = 1. -
SMIRN(Z).
IFCOD- A CODE DENOTING THE PARTICULAR THEORETICAL
PROBABILITY DISTRIBUTION FUNCTION BEING CONSIDERED.
= 1---F(X) IS THE NORMAL PDF.
= 2---F(X) IS THE EXPONENTIAL PDF.
= 3---F(X) IS THE CAUCHY PDF.
= 4---F(X) IS THE UNIFORM PDF.
= 5---F(X) IS USER SUPPLIED.
U - WHEN IFCOD IS 1 OR 2, U IS THE MEAN OF THE DENSITY
GIVEN ABOVE.
WHEN IFCOD IS 3, U IS THE MEDIAN OF THE CAUCHY
DENSITY.
WHEN IFCOD IS 4, U IS THE LEFT ENDPOINT OF THE
UNIFORM DENSITY.
WHEN IFCOD IS 5, U IS USER SPECIFIED.
S - WHEN IFCOD IS 1 OR 2, S IS THE STANDARD DEVIATION OF
DENSITY GIVEN ABOVE, AND SHOULD BE POSITIVE.
WHEN IFCOD IS 3, U - S SPECIFIES THE FIRST QUARTILE
OF THE CAUCHY DENSITY. S SHOULD BE NON-ZERO.
IF IFCOD IS 4, S IS THE RIGHT ENDPOINT OF THE UNIFORM
DENSITY. S SHOULD BE GREATER THAN U.
IF IFCOD IS 5, S IS USER SPECIFIED.
IER - ERROR INDICATOR WHICH IS NON-ZERO IF S VIOLATES ABOVE
CONVENTIONS. ON RETURN NO TEST HAS BEEN MADE, AND X
AND Y HAVE BEEN SORTED INTO MONOTONIC NON-DECREASING
SEQUENCES. IER IS SET TO ZERO ON ENTRY TO KOLMO.
IER IS CURRENTLY SET TO ONE IF THE USER-SUPPLIED PDF
IS REQUESTED FOR TESTING. THIS SHOULD BE CHANGED
(SEE REMARKS) WHEN SOME PDF IS SUPPLIED BY THE USER.
REMARKS
N SHOULD BE GREATER THAN OR EQUAL TO 100. (SEE THE
MATHEMATICAL DESCRIPTION GIVEN FOR THE PROGRAM SMIRN,
CONCERNING ASYMPTOTIC FORMULAE) ALSO, PROBABILITY LEVELS
DETERMINED BY THIS PROGRAM WILL NOT BE CORRECT IF THE
SAME SAMPLES ARE USED TO ESTIMATE PARAMETERS FOR THE
CONTINUOUS DISTRIBUTIONS WHICH ARE USED IN THIS TEST.
(SEE THE MATHEMATICAL DESCRIPTION FOR THIS PROGRAM)
F(X) SHOULD BE A CONTINUOUS FUNCTION.
ANY USER SUPPLIED CUMULATIVE PROBABILITY DISTRIBUTION
FUNCTION SHOULD BE CODED BEGINNING WITH STATEMENT 26 BELOW,
AND SHOULD RETURN TO STATEMENT 27.
DOUBLE PRECISION USAGE---IT IS DOUBTFUL THAT THE USER WILL
WISH TO PERFORM THIS TEST USING DOUBLE PRECISION ACCURACY.
IF ONE WISHES TO COMMUNICATE WITH KOLMO IN A DOUBLE
PRECISION PROGRAM, HE SHOULD CALL THE FORTRAN SUPPLIED
PROGRAM SNGL(X) PRIOR TO CALLING KOLMO, AND CALL THE
FORTRAN SUPPLIED PROGRAM DBLE(X) AFTER EXITING FROM KOLMO.
(NOTE THAT SUBROUTINE SMIRN DOES HAVE DOUBLE PRECISION
CAPABILITY AS SUPPLIED BY THIS PACKAGE.)
SUBROUTINES AND FUNCTION SUBPROGRAMS REQUIRED
SMIRN, NDTR, AND ANY USER SUPPLIED SUBROUTINES REQUIRED.
METHOD
FOR REFERENCE, SEE (1) W. FELLER--ON THE KOLMOGOROV-SMIRNOV
LIMIT THEOREMS FOR EMPIRICAL DISTRIBUTIONS--
ANNALS OF MATH. STAT., 19, 1948. 177-189,
(2) N. SMIRNOV--TABLE FOR ESTIMATING THE GOODNESS OF FIT
OF EMPIRICAL DISTRIBUTIONS--ANNALS OF MATH. STAT., 19,
1948. 279-281.
(3) R. VON MISES--MATHEMATICAL THEORY OF PROBABILITY AND
STATISTICS--ACADEMIC PRESS, NEW YORK, 1964. 490-493,
(4) B.V. GNEDENKO--THE THEORY OF PROBABILITY--CHELSEA
PUBLISHING COMPANY, NEW YORK, 1962. 384-401.