Population Distribution
Part I: Density Gradients
Density gradients measure the degree to which the density of something
diminishes with distance from some center associated with the variable of
interest. The most common application studies the decline in urban density with
distance from the urban center Also of interest is the decline in land values with
distance or the decline in market penetration.
For this assignment estimate a density gradient for one of the PaSSHE Schools
1.
Open the Density Gradient spreadsheet.
2.
Get the data from the Enroll spreadsheet
3.
Calculate density as students per 10,000 population. Use the natural
log function, =ln(A1), to calculate the natural log of density for each
county.
4.
Regress the natural log of density against distance
5.
Graph the Density Gradient
6.
Interpret the regression result
Part II: Index of Concentration
The Index of Concentration measures the degree to which two variables are
distributed in a similar or different fashion throughout some geographic territory.
The index runs from 0 if two distributions are the same and 1 if they are
completely different. For this assignment test whether the distributions of death
by gender are similar or different. Clearly one would expect to find that deaths
among men and women are distributed similarly around the state.
1.
Open the Index of Concentration spreadsheet and calculate the
required percentages.
2.
Use the Absolute Value function, =abs(A1), to calculate the absolute
differences between the percentages.
3.
Sum the absolute values and divide by 2 to get the index of
concentration.
4.
Interpret the results of the analysis.
1. Calculate the Aggregate Accessibility Index by dividing the population of
each county by the distance between itself and the other counties. Sum
the columns to get the accessibility index for each county.
2. Copy both results into the result table and compare the results. Which are
the most and least accessible counties for according to each measu