Assignment 7

The sex ratio for a population or age group is the ratio of the number of males to females. A related concept is what demographers call the marriage squeeze. On average, husbands tend to be a few years older than their wives, so the ratio of men in one age group to women in the next younger age group is an indication of whether or not there is a balance in the number of potential spouses for either sex. As you work within DemographyLab, answer the following questions to illustrate these concepts.


1 .		Choose any nation and compute the 1998 sex ratio for each age group. How does the sex ratio change with age? At what age does the sex ratio become close to 1? Repeat the computation for a second country. Are the trends similar?

2 .		Propose a hypothesis to explain differences in sex ratio with age. Test your hypothesis by altering the vital rates of a country and looking at the sex ratio of different age groups after 100 years of population change.

3 .		Using the Tabular Data view for the USA for 1998, compute the ratio of men 20–24 to women 15–29 to women 20–24 and so on, until you reach the last age group. At what ages is the marriage squeeze most pronounced? Compute the USA 1998 sex ratios for each group. Would the marriage squeeze be less of a problem if, on average, spouses were of the same age?

4 .		Choose and country and modify the fertility rates so that population growth is a large positive value, a large negative value, and ZPG. For each case, simulate 100 years of population growth and examine the sex ratio and marriage squeeze at the end of the 100 years. Is there an effect of population growth rate on sex ratios? Is there an effect of population growth rate on the marriage squeeze? Can you explain these results?