omom
asked on
life expectancy (survivorship) math
I need an function for crude life expectancy (that is a life expectancy based solely on genetics, no environmental considerations)
I would expect a curve of this equation to look like a gauss/normal distrubution weighted to the right of the median. Kinda like this:
|
| *
| * *
| * *
| * *
| * *
| * *
| * *
| * *
__________________________ __________ _______
A logarithmic normal distribution is close, but it looks like a guass/normal distrubution weighted to the right of the median.
|
| *
| * *
| * *
| * *
| * *
| * *
| * *
| * *
__________________________ __________ _______
x is age (in years)
y is # of lifeforms
-------------------------- -------
maybe this
x = age interval (often implicitly an interval) -this can be a month, year
Nx = survivors beginning at age interval x
lx = proportion of orgs surviving to start of x
dx = organisms dying between x and x+1
Derive subsequent columns from the data of x and Nx
dx = Nx+1 - Nx
lx = Nx / No
ex = the sum of all Lx from age x to the last age / N of age x
Lx = (Nx + Nx+1) / 2
I would expect a curve of this equation to look like a gauss/normal distrubution weighted to the right of the median. Kinda like this:
|
| *
| * *
| * *
| * *
| * *
| * *
| * *
| * *
__________________________
A logarithmic normal distribution is close, but it looks like a guass/normal distrubution weighted to the right of the median.
|
| *
| * *
| * *
| * *
| * *
| * *
| * *
| * *
__________________________
x is age (in years)
y is # of lifeforms
--------------------------
maybe this
x = age interval (often implicitly an interval) -this can be a month, year
Nx = survivors beginning at age interval x
lx = proportion of orgs surviving to start of x
dx = organisms dying between x and x+1
Derive subsequent columns from the data of x and Nx
dx = Nx+1 - Nx
lx = Nx / No
ex = the sum of all Lx from age x to the last age / N of age x
Lx = (Nx + Nx+1) / 2
ASKER CERTIFIED SOLUTION
membership
This solution is only available to members.
To access this solution, you must be a member of Experts Exchange.
ASKER
I think the gumbel distribution is what i'm looking for
Try this link for more info:
http://online.moraine.cc.il.us/Summer/2002/MTH139-303/lesson17.htm
Hope it helps.