100  REM ***** TVALUE ***** STATISTICS PROGRAM
110  REM ***** COMPUTES THE TWO-TAILED PROBABILITY OF A T-VALUE
235  PRINT "THERE IS A DISCONTINUITY IN THE APPROXIMATION FORMULA USED"
236  PRINT "IN THIS PROGRAM.  HOWEVER, THIS DISCONTINUITY WILL NOT AFFECT"
237  PRINT "VALUES IN THE CRITICAL RANGE."
238  PRINT 
240  PRINT "ENTER THE T-VALUE AND THE D. F."
250  INPUT G1,N
260  LET M=1
270  LET G=G1*G1
280  LET P=1
290  IF G*M*N=0 THEN 520
300  IF G<1 THEN 350
310  LET A=M
320  LET B=N
330 ET F=G
340  GOTO 380
350  LET A=N
360  LET B=M
370  LET F=1/G
380  LET A1=2/(9*A)
390  LET B1=2/(9*B)
400  LET Z=ABS((1-B1)*F^(.333333)-1+A1)
410  LET Z=Z/SQR(B1*F^(.666667)+A1)
420  IF B<4 THEN 460
430  LET P=(1+Z*(.196854+Z*(.115194+Z*(.000344+Z*.019527))))^4
440  LET P=.5/P
450  GOTO 480
460  LET Z=Z*(1+.08*Z^4/B^3)
470  GOTO 430
480  IF G<1 THEN 500
490  GOTO 540
500  LET P=1-P
510  GOTO 540
520  PRINT "YOU HAVE ERRED - INPUT THE TWO VALUES AGAIN."
530  GOTO 250
540  PRINT 
550PRINT 
560  PRINT "EXACT PROBABILITY OF T=";G1;" (TWO-TAILED TEST) WITH ";N;" D.F."
570  PRINT 
580  PRINT "    IS ";INT(100000.*P)/100000.
590  END