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Population
Studies cont'd
By
A. Swaby-Burton, Contributor
IN
THIS week's issue, I will again look
at a statistical question on demographic
studies.
Study
the tables below and answer the questions
that follow.
DEMOGRAPHIC
STATISTICS FOR JAMAICA 1965
1971
| Year |
Population
at Dec. 31
|
Births
|
Deaths
|
| 1969 |
1
846 256
|
64
668
|
14
094
|
| 1970 |
1
848 512
|
64
375
|
14
352
|
| 1971 |
1
911 400
|
66
271
|
14
078
|
| (Source:
World Heath Organisation) |
(a)
i) Calculate the crude birth rate
at December 31, 1969.
ii)
Calculate the crude death rate at
December 31, 1971.
(a)
i) Crude Birth Rate
=
Total birth in year 1969 x
1000
Average
total population for year
=
64,668 x 1000
1
846 256
Ans
= 35.02
ii)
Crude Death Rate
=
Total deaths in year 1971 x
1000
Average total population for year
=
14,078 x 1000
1
911 400
Ans = 7.36
(b)
Populations of region 4 in Guyana
by age group, by sex 1991. Using the
table below
(i)
Find the age dependency ratio for
region 4 in 1991.
(ii)
Suppose that 3,500 births were recorded
in region 4 in 1991, find the general
fertility rate for the region.
POPULATION
OF REGION 4 IN GUYANA BY AGE GROUP,
BY SEX (1991)
| Age
Group |
Total
|
Males
|
Females
|
| Both
sexes |
294,000
|
138,000
|
156,000
|
| 0-4 |
33,000
|
16,000
|
17,000
|
| 5-9 |
31,000
|
15,000
|
16,000
|
| 10-14 |
35,000
|
17,000
|
18,000
|
| 15-19 |
34,000
|
16,000
|
18,000
|
| 20-24 |
31,000
|
14,000
|
17,000
|
| 25-29 |
28,000
|
13,000
|
15,000
|
| 30-34 |
24,000
|
11,000
|
13,000
|
| 35-39 |
19,000
|
9,000
|
10,000
|
| 40-44 |
15,000
|
7,000
|
8,000
|
| 45-49 |
11,000
|
5,000
|
6,000
|
| 50-54 |
8,000
|
4,000
|
4,000
|
| 55-59 |
7,000
|
3,000
|
4,000
|
| 60-64 |
6,000
|
3,000
|
3,000
|
| 65
years and over |
12,000
|
5,000
|
7,000
|
| (Figures
in this table are calculated to
the nearest 1,000) |
(i)
Age dependency ratio
=
P 0-14 + P 65+ x 100
P 15 - P 64
= 99,000 + 12,000 x 100
183,000
=
111,000 x 100
183
Ans = 60.66
(ii)
General fertility rate:
=
No. of births in year 1991
x 100
Women
P15 - P44
=
3,500 x 100
81,000
Ans = 43.21
Try
this question on your own.
(a)
State the demographic or estimating
equation generally used by demographers
that symbolically represents the size
of population at any given time. Indicate
what is represented by each symbol.
(b)
The only demographic data you have
for an urban community are (i) its
present population and (iii) the vital
statistics on births and deaths over
the last ten years. Given that the
symbol 'm' represents net migration,
what equation will you use to obtain
net migration to and from the community?
Indicate what it represents by each
symbol of the equation.
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