John,
I stand corrected. I really guess I misunderstood what Mark wanted.
I now realize he is an experienced programmer. I'm sure that the correct
BASIC routines can be found in a number of books on programming. It seems to
me I remember that Apple produced a book quite some time ago and it had in it
the method of determining the probability of a Z value.
I looked back at some programming I did quite a while back and came up with
the following code. I hop that Mark can use it. I know it works in my
software but it is only one of about six or seven things the user might want
to know when dealing with Z values.
Depending on the actual basic language that is used (GWBASIC, QUICKBasic,
TurboBasic) this routine should find the probability of a given Z value to at
least the fourth decimal place.
Of course Mark could scan a copy of the Z table and then put it into a Word
document and load that onto the PalmPilot. That way he could quickly refer
to the table at any time.
I assume Mark can write the code for entering the values.
Here is the code, I hope it helps.
ZOnly:
Mean=0
St.Dev=1
PROMPT$=" Enter the Z value to compare to the MEAN "
X$="C"
PROMPT$=PROMPT$+PAD$ : PROMPT$=LEFT$(PROMPT$,57)
print PROMPT$;
input " ",X$
if X$="" OR X$=" " then X$="0"
IF X$="-" OR ASC(X$)<45 OR ASC(X$)>57 THEN
beep
print
print " Improper entry. Please try again."
print
goto GeneralMenu
END IF
XX=VAL(X$)
Y=XX : Y=ABS(Y)
IF Y=0 THEN
beep : print
print " Your entered value must not be zero. Please try again."
print
input " Depress <Enter> to continue ",rck$
goto GeneralMenu:
END IF
Y=ABS((Y-Mean)/St.Dev)
StandDevAway=Y
R=EXP(-(Y^2)/2)/2.5066282746
goto DoCalc
ZRawData:
print
PROMPT$=" Enter the POPULATION MEAN value "
X$="C"
PROMPT$=PROMPT$+PAD$ : PROMPT$=LEFT$(PROMPT$,57)
print PROMPT$;
input " ",X$
if X$="" OR X$=" " then X$="0"
IF X$="-" OR ASC(X$)<45 OR ASC(X$)>57 THEN
beep
print
print " Improper entry. Please try again."
print
goto GeneralMenu
END IF
XX=VAL(X$)
Mean=XX
St.Dev=-1
WHILE St.Dev<=0
PROMPT$=" Enter the POPULATION STANDARD DEVIATION "
X$="C"
PROMPT$=PROMPT$+PAD$ : PROMPT$=LEFT$(PROMPT$,57)
print PROMPT$;
input " ",X$
if VAL(X$)=-999 then goto OnToMenu
if X$="" or X$=" " then X$="0"
if X$="-" then X$="0"
if ASC(X$)<45 or ASC(X$)>57 then X$="0"
XX=VAL(X$)
IF XX<=0 THEN
beep
print
print " The Standard Deviation must be a positive number."
input " Please try again. Depress <Enter> to continue ",rck$
END IF
St.Dev=XX
WEND
AskStxx:
St.Dev=St.Dev/(SQR(SSize))
print
print " Remember if you are comparing a value to the Mean you may want"
print " to enter lower class limit of that value. For instance, if you"
print " are interested in a value of 13 you might want to enter 12.5."
print
PROMPT$=" Enter the value to compare to the MEAN "
X$="C"
PROMPT$=PROMPT$+PAD$ : PROMPT$=LEFT$(PROMPT$,57)
print PROMPT$;
input " ",X$
if VAL(X$)=-999 then goto OnToMenu
if X$="" or X$=" " then X$=STR$(Mean)
if ASC(X$)<45 or ASC(X$)>57 then X$=STR$(Mean)
XX=VAL(X$)
Y=XX ': Y=ABS(Y)
IF Y=Mean THEN
beep : print
print " Your entered a value that is equal to the Mean. This results"
print " in a Z value of 0.
goto DoneShowing
END IF
Interest=Y
Y=ABS((Y-Mean)/St.Dev)
Top=Interest-Mean
StandDevAway=Y
R=EXP(-(StandDevAway^2)/2)/2.5066282746
DoCalc:
cls : locate 4,1
if Top<0 then
StandDevAway=StandDevAway*(-1)
if SSize=1 then
kk=abs(Top)
print " The score entered is ";
print using fnform$(kk);abs(Top);
print " less than the Mean."
end if
end if
print " For a Z value of "; : print using FORM14$;StandDevAway
print
print " (y Ordinate at Z) FREQUENCY = ";
print using FORM14$; R
Z=Y
Y=1/(1+.33267*ABS(Y))
T=1-R*(.4361836*Y-.1201676*Y^2+.937298*Y^3)
if Z<0 then T=1-T
print
print " (Area in Larger Portion) PROBABILITY = ";
print using FORM14$; T
print " (Area in Smaller Portion one-tail = ";
print using FORM14$; 1-T
print " (Area from Z to Mean one-tail = ";
print using FORM14$; .5-(1-T)
print " (Area in Smaller Portions two-tail = ";
print using FORM14$; (1-T)*2
print
DoneShowing:
Seems as though this is like re-inventing the wheel and I'm not sure if he
helps to understand Z values or probability.
GOD BLESS AMERICA
Dr. Robert C. Knodt
4949 Samish Way, #31
Bellingham, WA 98226
[EMAIL PROTECTED]
"The vocation of every man and woman is to serve other people." -- Tolstoy
=================================================================
Instructions for joining and leaving this list and remarks about
the problem of INAPPROPRIATE MESSAGES are available at
http://jse.stat.ncsu.edu/
=================================================================
