Age (x) (years) Number Surviving (n x ) Proportion Surviving (l x ) log(n x ) Fe
ID: 589859 • Letter: A
Question
Age (x) (years)
Number Surviving (nx)
Proportion Surviving (lx)
log(nx)
Fecundity (fx)
lx fx
x lx fx
0
80,000
1.0
0
0
0
1
750
0.009375
0.1
0.0009375
0.0009375
2
400
0.005
2
0.01
0.02
3
320
0.004
80
0.32
0.96
4
240
0.003
120
0.36
1.44
5
80
0.001
160
0.16
0.8
calculate the lognx, and this is the answer from our professor:
Age (x) (years)
Number Surviving (nx)
Proportion Surviving (lx)
log(nx)
Fecundity (fx)
0
80,000
1.0
3.0
0
1
750
0.009
0.972
0.1
2
400
0.005
0.699
2
3
320
0.004
0.602
80
4
240
0.003
0.477
120
5
80
0.001
0.000
160
Why??? log (80,000)=4.903, why his answer is 3.0????
Age (x) (years)
Number Surviving (nx)
Proportion Surviving (lx)
log(nx)
Fecundity (fx)
lx fx
x lx fx
0
80,000
1.0
0
0
0
1
750
0.009375
0.1
0.0009375
0.0009375
2
400
0.005
2
0.01
0.02
3
320
0.004
80
0.32
0.96
4
240
0.003
120
0.36
1.44
5
80
0.001
160
0.16
0.8
Explanation / Answer
For age = 5 years,
Log (80) = 1.903
But it is written 0.000
Actually from all the log(nx) values, 1.903 is subtracted.
For example, for age = 0 years, log (80000) = 4.903
log 80000 - 1.903 = 3.0
Similar is the case for all the ages.
The professor has subtracted 1.903 from each answer. Normally, this is done because it is easy to compare the results with relative to each other. If we keep the original values, then it becomes difficult to compare them. We make one value as zero, and compare the rest with that value.