Average lifespan=
	avg lifespan lookup(Population density)
	~	years
	~		|

avg lifespan lookup(
	[(0,0)-(1.2,100)],(0,60),(0.2,72),(0.4,78),(0.6,75),(0.8,60),(1,35),(1.2,20))
	~	years
	~		|

Carrying capacity=
	4000
	~	people
	~		|

Births per person per year=
	0.03
	~	1/Year
	~		|

Population density=
	Population/Carrying capacity
	~	Dmnl
	~		|

Births=
	Births per person per year*Population
	~	people/Year
	~		|

Deaths=
	Population/Average lifespan
	~	people/Year
	~		|

Population= INTEG (
	Births-Deaths,
		1000)
	~	people
	~		|

********************************************************
	.Control
********************************************************~
		Simulation Control Paramaters
	|

FINAL TIME  = 300
	~	Year
	~	The final time for the simulation.
	|

INITIAL TIME  = 0
	~	Year
	~	The initial time for the simulation.
	|

SAVEPER  = 1
	~	Year
	~	The frequency with which output is stored.
	|

TIME STEP  = 0.25
	~	Year
	~	The time step for the simulation.
	|

\\\---/// Sketch information - do not modify anything except names
V300  Do not put anything below this section - it will be ignored
*View 1
$192-192-192,0,Comic Sans MS|18||0-0-0|0-0-0|0-0-255|-1--1--1|-1--1--1|72,72
10,1,Population,368,84,47,24,3,3,0,40,0,0,0,0,0-0-0,0-0-0,Comic Sans MS|18||0-0-0
12,2,48,190,82,8,8,0,3,0,40,-1,0,0,0,0-0-0,0-0-0,Comic Sans MS|18||0-0-0
1,3,5,1,4,0,0,22,0,0,0,-1--1--1,,1|(287,83)|
1,4,5,2,100,0,0,22,0,0,0,-1--1--1,,1|(220,83)|
11,5,48,248,83,6,8,34,3,0,0,1,0,0,0
10,6,Births,248,105,28,14,40,3,0,40,-1,0,0,0,0-0-0,0-0-0,Comic Sans MS|18||0-0-0
12,7,48,544,82,8,8,0,3,0,40,-1,0,0,0,0-0-0,0-0-0,Comic Sans MS|18||0-0-0
1,8,10,7,4,0,0,22,0,0,0,-1--1--1,,1|(510,82)|
1,9,10,1,100,0,0,22,0,0,0,-1--1--1,,1|(443,82)|
11,10,48,478,82,6,8,34,3,0,0,1,0,0,0
10,11,Deaths,478,104,32,14,40,3,0,40,-1,0,0,0,0-0-0,0-0-0,Comic Sans MS|18||0-0-0
1,12,1,11,1,2,0,0,0,64,0,-1--1--1,,1|(445,148)|
1,13,1,6,1,1,0,0,0,64,0,-1--1--1,,1|(313,152)|
10,14,Births per person per year,181,180,69,27,8,3,1,40,0,0,0,0,0-0-0,0-0-0,Comic Sans MS|18||0-0-0
10,15,Average lifespan,522,184,44,25,8,3,2,40,0,0,0,0,0-0-0,0-0-0,Comic Sans MS|18||0-0-0
1,16,14,6,1,1,0,0,0,64,0,-1--1--1,,1|(196,141)|
1,17,15,11,1,2,0,0,0,64,0,-1--1--1,,1|(525,146)|
10,18,Population density,368,242,44,25,8,3,3,0,0,0,0,0
10,19,Carrying capacity,367,330,38,25,8,3,3,0,0,0,0,0
1,20,18,15,1,3,0,0,0,64,0,-1--1--1,,1|(483,247)|
1,21,19,18,0,3,0,0,0,64,0,-1--1--1,,1|(367,293)|
1,22,1,18,0,3,0,0,0,64,0,-1--1--1,,1|(368,155)|
12,23,0,297,118,15,14,8,4,1,0,-1,0,0,0
(R)
12,24,0,423,120,15,14,8,4,2,0,-1,0,0,0
(B)
12,25,0,440,192,15,14,8,4,3,0,-1,0,0,0
(B)
10,26,avg lifespan lookup,594,275,53,25,8,3,4,0,0,0,0,0
1,27,26,15,0,4,0,0,0,64,0,-1--1--1,,1|(562,234)|
///---\\\
:GRAPH POPULATION,_BIRTHS,_AND_
:TITLE Population, births, and deaths
:WIP
:X-DIV 6
:MAX-POINTS 2000
:SCALE
:VAR Population
:Y-MIN 0
:Y-MAX 6000
:LINE-WIDTH 2
:SCALE
:VAR Births
:Y-MIN 0
:Y-MAX 200
:LINE-WIDTH 2
:VAR Deaths
:LINE-WIDTH 2
:SCALE
:VAR Average lifespan
:Y-MIN 0
:Y-MAX 80
:LINE-WIDTH 2
:L<%^E!@
1:lower br.vdf
1:constrained pop.vdf
1:births&deaths.vdf
9:lower br
22:transaction,transactions
22:year,years
18::GPR's Powerbook:Documents-Vensim:PAD 724 models:Pop sensitivity.vpd
20::GPR's Powerbook:Documents-Vensim:PAD 724 models:Pop sens save.lst
15:0,0,0,0,0,0
19:100,0
27:0,
4:Time
5:Average lifespan
24:0
25:300
26:300