Computes area under normal curve up to any Z-score.
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* NORMAL.80 for the TI-80 *
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ACKNOWLEDGMENT
NORMAL.82P was written by Chuck Vonder Embse, a professor at Michigan State University, and is released to the public domain. It was converted to NORMAL.80 for the TI-80 by Dave Jaklitsch. You may copy and change this program.
INTRODUCTION
This program gives the area under the normal curve up to any Z-score (one or two tails). Graphics are optional.
HOW TO USE NORMAL
Set the calculator to Function graphing mode. Type prgmNORMAL and enter to run the program. The program first prompts you to enter 1 for 1 tail or 2 for 2 tails. You are then prompted to enter the Z value. If you want to see the normal curve graphed and the region shaded, type 1 and enter; otherwise, type 2 and enter. If you chose to graph the curve, hit enter when the graph is completed and the value for P(Z) is displayed.
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\START80\
\COMMENT=Program file dated 04/20/93, 10:33
\NAME=NORMAL
\FILE=NORMAL.80
:CLRHOME
:FIX 4
:DISP "NORMAL CURVE"
:DISP "1=1 TAIL"
:INPUT "2=2 TAILS ",C
:INPUT "Z=",Z
:0->F
:If Z\<=\0
:1->F
:INPUT "GRAPH?(Y=1,N=2)",N
:If N=2
:Goto 1
:FNOFF
:"(1/\sqrt\2\pi\)e^(\(-)\.5X\^2\)"->Y1:\(-)\4.0->XMIN
:4.0->XMAX
:1->XSCL:\(-)\.2->YMIN
:.6->YMAX
:.1->YSCL
:DISPGRAPH
:LINE(Z,0,Z,Y1(Z))
:IF C=2
:LINE(\(-)\Z,0,\(-)\Z,Y1(\(-)\Z))
:IF C=1
:SHADE(0,Y1,1,\(-)\4,Z)
:ABS Z->Z
:IF C=2
:SHADE(0,Y1,1,\(-)\Z,Z)
:PAUSE
:LBL 1
:ABS Z->Z
:1/(1+.2316419Z)\->\T
:(1/\sqrt\2\pi\)e^(\(-)\.5Z\^2\)->Q
:Q(.31938153T-.356563782T\^2\+1.78147937T\^3\-1.821255978T^4+1.330274429T^5)->P
:IF N=1
:DISP "P(Z)=AREA SHADED"
:DISP "P(Z)="
:IF C=1
:THEN
:IF F=0
:DISP 1-P
:END
:IF C=1
:THEN
:IF F=1
:DISP P
:END
:IF C=2:DISP 1-2P
\STOP80\
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