Page 60 - NG2022_merged
P. 60
Formula:
- If data is available at two time points (base and end of the short term,
usually a year), then use the following formula:
P0 + P1
Ptb =
2
Where:
Ptb: Average population;
P0: Population at the base period;
P1: Population at the ending period.
- If data is available at times evenly, then use the formula:
P0 Pn
+ P1 + .... + Pn-1 + 2
Ptb = 2
n
Where:
Ptb: Average population;
P0,1,...,n: Population at time points of 0, 1,...,;
n: Number of equal time points.
- If data are available at times unequal spaces, using the formula:
Ptb1t1 + Ptb2t2 + .... + Ptbntn
Ptb =
∑ti
Where:
Ptb: Average population;
Ptb1: Average population of the first duration;
Ptb2: Average population of the second duration;
th
Ptbn: Average population of the n duration;
th
ti: Length of the i duration.
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