f90: Pearson's Chi-square test. Test the frequency distributions of categorical variables in a table of frequencies. *.exe and *.out are the Windows and Linux executables.

chisq_test.exe

chisq_test.f90

PROGRAM chisq_test

IMPLICIT NONE

! Declarations

INTEGER:: i, j, m, n, df, error
INTEGER,DIMENSION(:,:),ALLOCATABLE:: o
REAL:: chi
REAL,DIMENSION(:,:),ALLOCATABLE:: e, c
 CHARACTER(20):: infile, exiit

! Opening prints

PRINT*,
PRINT*,
PRINT*, 'This program is written by Mohammad A. Nilforooshan.'
PRINT*, 'All rights reserved.'
PRINT*, 'http://sites.google.com/site/mannprofile/'

! Ask for the input file, open and check it

PRINT*,
PRINT*,
PRINT*, 'Type the name of the input file.'
READ*, infile
OPEN(UNIT=10, FILE=infile, STATUS='OLD', IOSTAT=error)

IF (error/=0) THEN
    PRINT*,
    PRINT*,
    PRINT*, 'Error reading file.'
    STOP
END IF

! Ask for the size of the matrix

PRINT*,
PRINT*,
PRINT*, 'Insert the number of rows.'
READ*, m
PRINT*, 'Insert the number of columns.'
READ*, n

IF (m>9 .OR. n>9) THEN
    PRINT*,
    PRINT*,
    PRINT*, 'Sorry, up to 9 rows/columns is supprted.'
    PRINT*, 'Contact the programmer to get more space.'
    STOP
END IF

! Read the data

ALLOCATE(o(m,n))
READ(10,*) ((o(i,j),j=1,n),i=1,m)

! Create the matrix of expectations

ALLOCATE(e(m,n))

DO i=1,m
    DO j=1,n
        e(i,j)=SUM(o(i,:))*SUM(o(:,j))/REAL(SUM(o(:,:)))
    END DO
END DO

! Estimate the Chisq table and the Chisq value

ALLOCATE(c(m,n))

DO i=1,m
    DO j=1,n
        c(i,j)=((o(i,j)-e(i,j))**2)/REAL(e(i,j))
    END DO
END DO

 df=(m-1)*(n-1)
 chi=SUM(c(:,:))

! Write the results on the screen

PRINT*,
PRINT*,
PRINT*, 'Observed frequencies:'
PRINT*, '---------------------'
DO i=1,m
    WRITE(*,'(9I6)') (o(i,j), j=1,n)
END DO
PRINT*, '---------------------'
PRINT*,
PRINT*,
PRINT*, 'Expected frequencies:'
PRINT*, '---------------------'
DO i=1,m
    WRITE(*,'(9F9.2)') (e(i,j), j=1,n)
END DO
PRINT*, '---------------------'
PRINT*,
PRINT*,
PRINT*, 'Chi-sqrd proportions:'
PRINT*, '---------------------'
DO i=1,m
    WRITE(*,'(9F7.3)') (c(i,j), j=1,n)
END DO
PRINT*, '---------------------'
PRINT*,
PRINT*,
WRITE(*,'(A,F6.3,A,I2)') 'Chi-squared = ',chi,', df = ',df

PRINT*,
PRINT*,
PRINT*, 'Press any key to exit.'
READ*, exiit

IF (exiit=='a') THEN
GO TO 120
END IF

120 END PROGRAM chisq_test

chisq_test.out