CZ:Featured article/Current: Difference between revisions

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A '''[[geometric series]]''' is a series associated with a geometric sequence,
'''[[Fertility (demography)]]''' is the demographic analysis of having babies.  
i.e., the ratio (or quotient) ''q'' of two consecutive terms is the same for each pair.  


Thus, every geometric series has the form
Fertility is having babies. Couples do it, and so too do entire societies, in a way. Therefore we approach the topic at both the individual and the social level. At the individual level, the statistics are normally analyzed in terms of the mother, though admittedly the father plays a role as well. At the social level we measure fertility with different rates using birth statistics and census data. Research on fertility inside the United States has slowed in recent decades, because most of the important questions have been answered. nearly identical. There has been a shift from a focus on fertility as the basis of population growth to one of fertility as a component of health, marital and family-building patterns, and the connection to women's employment and careerism. There has been new attention to racial and ethnic patterns, and to the fertility of unmarried women. Attention has shifted to historical patterns in the US and Europe, going back to the year 1600. Even more important, attention has shifted to the rapid growth of population in developing countries, especially in Asia, Africa and Latin America. In terms of world population, the main issue is the overall number of births, and how it can be reduced.
:<math>
====Measuring Fertility====
a + aq + aq^2 + aq^3 + \cdots
The most basic measurement of fertility is the number of births; combined with deaths and migration, it permits the calculation of population change. To compare countries or groups, we must relate the number of births to the total population ("crude" birth rate) or to the number of women at risk (various measures.)
</math>
where the quotient (ratio) of the (''n''+1)th  and the ''n''th term  is
:<math>
\frac{a q^{n}}{aq^{n-1}} = q.
</math>


The sum of the first ''n'' terms of  a geometric sequence is called the ''n''-th partial sum (of the series); its formula is given below (''S''<sub>''n''</sub>).
''[[Fertility (demography)|.... (read more)]]''
 
An infinite geometric series (i.e., a series with an infinite number of terms) converges if and only if |''q''|<1, in which case its sum is <math> a \over 1-q </math>, where ''a'' is the first term of the series.
 
In finance, since compound interest generates a geometric sequence,
regular payments together with compound interest lead to a geometric series.
 
''[[Geometric series|.... (read more)]]''

Revision as of 20:35, 14 October 2011

Fertility (demography) is the demographic analysis of having babies.

Fertility is having babies. Couples do it, and so too do entire societies, in a way. Therefore we approach the topic at both the individual and the social level. At the individual level, the statistics are normally analyzed in terms of the mother, though admittedly the father plays a role as well. At the social level we measure fertility with different rates using birth statistics and census data. Research on fertility inside the United States has slowed in recent decades, because most of the important questions have been answered. nearly identical. There has been a shift from a focus on fertility as the basis of population growth to one of fertility as a component of health, marital and family-building patterns, and the connection to women's employment and careerism. There has been new attention to racial and ethnic patterns, and to the fertility of unmarried women. Attention has shifted to historical patterns in the US and Europe, going back to the year 1600. Even more important, attention has shifted to the rapid growth of population in developing countries, especially in Asia, Africa and Latin America. In terms of world population, the main issue is the overall number of births, and how it can be reduced.

Measuring Fertility

The most basic measurement of fertility is the number of births; combined with deaths and migration, it permits the calculation of population change. To compare countries or groups, we must relate the number of births to the total population ("crude" birth rate) or to the number of women at risk (various measures.)

.... (read more)

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