Population Projection: Cases
Use the following information to answer the questions below:
Blue Earth County, MN--1980
CURRENT MALE MALE CURRNT FEMALE FEMALE BIRTHRT
MALE SURVIV MIGRATN FEMALE SURVIV MIGRATN PER1OOO
COHORT POP RATE RATE POP RATE RATE FEMALES
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75+ 958 .523 .024 1811 .672 .093
70-74 610 .766 -.010 873 .876 -.010
65-69 943 .831 -.013 943 .916 -.011
60-64 830 .882 -.010 1145 .945 -.009
55-59 1065 .925 .010 1155 .963 .008
50-54 1071 .952 -.018 1128 .975 -.019
45-49 1047 .969 -.018 1051 .983 -.019
40-44 920 .983 -.097 1066 .989 -.061 18.2
35-39 1371 .989 -.109 1193 .993 -.070 18.2
30-34 1779 .993 -.402 1685 .996 -.465 69.4
25-29 2581 .993 -.115 2258 .997 -.304 140.4
20-24 3958 .992 .250 4211 .997 .298 72.4
15-19 2985 .992 .131 3226 .997 .201 30.1
10-14 1814 .995 -.034 1696 .998 -.051
5-9 1538 .998 -.118 1532 .999 -.083
0-4 2000 .998 -.038 1871 .998 -.012
M/F RATIO = 0.51
- What do you project to be the population of Blue Earth County
in the year 2000?
- Blue Earth County population figures are heavily influenced
by Mankato State University. Suppose the University were absent,
and the 1980 data were adjusted to reflect the rates in surrounding
rural counties:
CURRENT MALE MALE CURRNT FEMALE FEMALE BIRTHRT
MALE SURVIV MIGRATN FEMALE SURVIV MIGRATN PER1OOO
COHORT POP RATE RATE POP RATE RATE FEMALES
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40-44 21.3
35-39 21.3
30-34 -.207 -.144 81.6
25-29 .020 -.103 172.3
20-24 2465 -.037 2393 -.052 170.6
15-19 2301 -.105 2179 -.065 36.9
Now how would you project the population of blue Earth County
for the year 2000?
- Suppose the University remained, but the fertility rate came
more in line with neighboring communities (i.e., the college population
showed the same childbearing patterns as others in the County).
What effect would this change in fertility have on the population
of Blue Earth County by the year 2000?
- Suppose the Governor helped the city attract a major manufacturing
plant, one that would hire 2500 new employees. Assume that unemployment
is low enough that most of the new jobs will attract migrants
to the area. Most of them will be 20-24 year-old males (40%)
and females (20%). 20% will be 25-29 year-old males, 10% females
age 25-29; 8% will be 30-34 year-old males, 2% females age 30-34.
The average household will bring 0.7 spouses (adults of the same
age cohort, opposite sex), 1.0 children age 0-4, 0.5 children
age 5-9, and 0.25 children age 10-14. What effect will this single
plant have on the population of Blue Earth County by the year
2000, assuming the newcomers follow the same fertility and migration
patterns once they arrive?
- Suppose medical science manages to extend life expectancy,
changing the survival rate for the oldest cohort to 0.66 for men
and 0.77 for women. What effect will this have on the population
of Blue Earth County by the year 2000?
© 1996 A.J.Filipovitch
Revised 18 October 96