<P> Population pyramids often contain continuous stacked - histogram bars, making it a horizontal bar diagram . The population size is depicted on the x-axis (horizontal) while the age - groups are represented on the y - axis (vertical). The size of the population can either be measured as a percentage of the total population or by raw number . Males are conventionally shown on the left and females on the right . Population pyramids are often viewed as the most effective way to graphically depict the age and distribution of a population, partly because of the very clear image these pyramids represent . A great deal of information about the population broken down by age and sex can be read from a population pyramid, and this can shed light on the extent of development and other aspects of the population . </P> <P> The measures of central tendency, mean, median, and mode, should be considered when assessing a population pyramid . since the data is not completely accurate . For example, the average age could be used to determine the type of population in a particular region . A population with an average age of 15 would have a young population compared to a population that has an average age of 55, which would be considered an older population . It is also important to consider these measures because the collected data is not completely accurate . The mid-year population is often used in calculations to account for the number of births and deaths that occur . </P> <P> A population pyramid gives a clear picture of how a country transitions from high fertility to low fertility rate . The broad base of the pyramid means the majority of population lies between ages 0--14, which tells us that the fertility rate of the country is high and above population sub-replacement fertility level . The older population is declining over time due to a shorter life expectancy of sixty years . However, there are still more females than males in these ranges since women have a longer life expectancy . As reported by the Proceedings of the National Academy of Sciences, women tend to live longer than men because women do not partake in risky behaviors . Also, Weeks' Population: an Introduction to Concepts and Issues, considered that the sex ratio gap for the older ages will shrink due to women's health declining due to the effects of smoking, as suggested by the United Nations and U.S. Census Bureau . Moreover, it can also reveal the age - dependency ratio of a population . Populations with a big base, young population, or a big top, an older population, shows that there is a higher dependency ratio . The dependency ratio refers to how many people are dependent on the working class (ages 15--64). According to Weeks' Population: an Introduction to Concepts and Issues, population pyramids can be used to predict the future, known as a population forecast . Population momentum, when a population's birth rates continue to increase even after replacement level has been reached, can even be predicted if a population has a low mortality rate since the population will continue to grow . This then brings up the term doubling time, which is used to predict when the population will double in size . Lastly, a population pyramid can even give insight on the economic status of a country from the age stratification since the distribution of supplies are not evenly distributed through a population . </P> <P> In the demographic transition model, the size and shape of population pyramids vary . In stage one of the demographic transition model, the pyramids have the most defined shape . They have the ideal big base and skinny top . In stage two, the pyramid looks similar, but starts to widen in the middle age groups . In stage three, the pyramids start to round out and look similar in shape to a tombstone . In stage four, there is a decrease in the younger age groups . This causes the base of the widened pyramid to narrow . Lastly, in stage five, the pyramid starts to take on the shape of a kite as the base continues to decrease . The shape of the population is dependent upon what the economy is like in the country . More developed countries can be found in stages three four and five while the least developed countries have a population represented by the pyramids in stages one and two . </P>

Which age group of population indicates the largest working population