Microcomputer
and Technology
Applications
^^
Program To Calculate Means and
Standard Deviations
We have recently developed a short but useful program
to calculate means and standard deviations in sample sizes
of up to 1924 numbers between zero and 65024. The data
can be entered without knowing how many entries there
are since the program will count and save the entries and
then calculate the mean, variance, and standard deviation. It can also perform the calculations in numbers of
up to four decimal places as long as there are no more
t h a n five characters (excluding the decimal point) and the
numbers are all the same order of magnitude.
To complete the data entry, enter the number 65025,
which has been designated as terminator and initiates the
mean routine.
Although the program is written for the Commodore
64, it can be easily adapted to other computers. Care must
be taken to select a location into which to poke and peek
the values (lines 110, 260, 270, 310, and 410) that will not
interfere with the BASIC operating system. For the Commodore, that location is 49152.
The program may be obtained on disk by mailing $5.00
for postage and handling to Magali Huertas, MT(ASCP),
712 Livezey L a n e , P h i l a d e l p h i a , PA 19128.—Magali
Huertas, MT(ASCP), and Geronimo Lluberas-Acosta, MD,
Philadelphia.
READY
10 REM:PROGRAM TO CALCULATE MEAN AND
STANDARD DEVIATION
20 REM:BYMAGALI HUERTAS, M.T. AND GERONIMO
LLUBERAS-ACOSTA, M.D.
30 POKE53280,0:POKE53281,0:POKE646,1
35 PRINT""
40 PRINT" wait while memory loci are cleared"
100 for i=0to3848
110 poke 49152 + i,0:next
120 print" start program 1"
123 print" instructions 2"
125 print""
128 prinf'PRESS 1 OR 2 AND RETURN";:
INPUTV:IFV<10RV>2THEN128
130 IFV = 2THENGOSUB600
140 PRINT" choose data format"
142 prinf'whole numbers
0"
144 prinf'one decimal place
1"
146 prinftwo decimal places
2"
148 prinf'three decimal places 3"
150 prinf'four decimal places
4"
155 print" "
160 prinf'ENTER YOUR CHOICE (0 TO 4)";:INPUTFM
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IFFM<0ORFM>4THEN160
PRINT" hardcopy of the analysis?"
print""
print" PRESS T FOR YES OR 'N' FOR
NO";:INPUTPR$
IFPR$o"N"THEN175
E = 1924
FOR I = OTOE
Q=l+1
PRINT"ENTRY#"; Q; " = "; :INPUTX
IFX = 65025THENN = l:GOTO290
X = X*10fFM
P = INT(X/255):POKE49152 + (2*I),P
R = X - (P*255):POKE49153 + (2*I),R
NEXT
T=0
FORI = 0TO(N-1)
S = ((PEEK(49152 + (2*l)))*255 + PEEK
(49153 + (2*l)))/10fFM
T = T + S:NEXT
AV = T/N:AV = (INT(AV* 1000))/1000
IFPR$ = "Y"THENOPEN4, 4, 7
PRINT""
PRINT"#"; TAB(5); "X"; TAB(14); " X - M " ;
TAB(26);"(X-M)t2"
K = 0:L = 0:J = 0
FORI = 0TO(N-1)
S = ((PEEK(49152 + (2I)))*255 + PEEK
(49153 + (2*I)))/10|FM
L = ABS(AV - S):L = (INT(L*1000))/1000
K = L|2:Q = I + 1
PRINTQ; TAB(4); S; TAB(12); L; TAB(24); K
IFPR$ = "Y"THENPRINT#4,Q;TAB(4); S;
TAb(8);L;TAB(10);K
J = J + K:NEXT
F = J/(N-1)
SD = F|(1/2)
SD = (INT(SD*1000))/1000
PRINT"N = ";
PRINT"MEAN = "; AV
PRINT"VARIANCE = ";F
PRINT'STANDARD DEVIATION = "TAB(12); SD
IFPR$ = "N"THENGOTO550
PRINT#4,"N= "; N
PRINT#4,"MEAN= "; AV
PRINT#4,"VARIANCE= "; F
PRINT#4, "STANDARD DEVIATION = "; TAB(6); SD
CLOSE 4
END
LABORATORY MEDICINE • VOL. 17, NO. 7, JULY 1986 419
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PRINT'this program is designed to calculate"
prinf'mean, variance and standard deviation"
prinf'of a group of up to 1924 numbers be-"
print'lween 0 and 65024 of no more than five"
prinf'characters (excluding decimal point)"
prinfeach."
prinf'press return to continue.":input
prinf'after completing the entry the number"
print"
print"65025"
print"
prinf'should be entered, this will indicate"
prinf'to the computer that the sequence is"
prinfcomplete."
prinf'press return to continue.":input
return
Correlations
This program studies the relationship of two sets of results. It can be used to correlate two methods or two tests.
The program is written for the Commodore 64 or Vic-20
in BASIC and can be easily translated into other basic
forms.
The program will accept up to 200 inputs (100 for each
of the two values) and will stop and do all the required
calculations by merely typing "stop" or "end" as a reference value after the last "real" value. It can be previewed
on the screen, and a hard copy option is available to those
with a printer.
The printout or screen view will show a comparison of
all values, t h e slope, y intercept "y," and correlation "r."
All t h a t is needed is graph paper (to plot the study).—Ron
Sorochin, BS, MT(ASCP), Jones Memorial Hospital,
Wellsville, NY.
101
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PRINT:INPUT" TEST EVALUATED";TE$
DIMR$(100),T$(100);N = 0
DIMR(100),T(100)
PRINT:PRINT:INPUT" REFERENCE METHOD";RM$
:PRINT.INPUT" TEST METHOD";TM$
FORQ=1TO100
PRINT:PRINT"
PLEASE ENTER REFERENCE
VALUE ":
120 PRINT"
THEN TEST VALUE":INPUTR$(Q),T$(Q)
124 IFR$(Q) = "STOP"ORR$(Q) = "END"THENGOTO130
125 :N = N + 1: NEXT
130 FORW = 1TON
131 R(W) = VAL(R$(W)):T(W) = VAL(T$(W))
135 Z = R(W)
136 X = X + Z
137 NEXT
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FORW=1TON
U=T(W)
Y = Y+U
NEXT
PRINT" REFERENCE TOTAL " X
PRINTPRINT" TEST TOTAL
"Y
FORW=1TON
ZZ = R(W)*R(W)
XX = XX + ZZ
NEXT
FORW=1TON
UU = T(W)*T(W)
YY = YY + UU
NEXT
PRINTPRINTTOTAL X f 2 ="XX
PRINTPRINTTOTAL Y j 2 = "YY
FORW=1TON
KK = R(W)*T(W)
LL = LL + KK
NEXT
PRINTPRINTTOTAL X*Y = "LL
INPUT" NEED HARDCOPY Y/N";HC$
IFHC$ = "Y"THENGOTO250
INPUT'SCREEN VIEWING (S) OR END (E)";IY$
IFIY$ = "E"THENEND
IFHC$ = "N"GOT0252
OPEN1,4:CMD1
PRINTPRINT'CORRELATION STUDY FOR - "TE$
PRINT" REFERENCE - "RM$" TEST - "TM$
PRINT"
PRINT" REFERENCE
TEST"
PRINT"
FORQ=1TON
"T(Q)
PRINT"
"R(Q)"
NEXT
M = (LL-((X*Y)/N))/(XX-((X | 2)/N))
"INT(M*100+.5)/
PRINTPRINT"
SLOPE =
100
400 B = Y/N-(M*(X/N))
Y INTERCEPT =
410 PRINTPRINT"
"INT(B*100 + .5)/100
600 R = ((N*LL)-(X*Y))/(SQR(((N*XX)-(X*X))*((N*YY)(Y-Y))))
R (COEFF) = "INT(R*100 + .5)/
620 PRINTPRINT"
100
622 PRINTPRINT"
ACCEPTABLE
NOT ACCEPTABLE
623 PRINT"
TECH
DATE
RV'D
DATE
624 PRINT"
625 IFHC$()"Y"GOT0245
1000 IFHC$ = "Y"THEN PRINT#1,4:CLOSE1
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The Editors.
focused exclusively on this field, and commentary on the
pleasures and frustrations involved in the experience of mi420 LABORATORY MEDICINE • VOL. 17, NO. 7, JULY 1986