# Population Density Help

• Oct 23rd 2009, 06:34 AM
allyourbass2212
Population Density Help
Basically I downloaded some information from that lists population density per a census block group, but their population density calculation doesn't seem to be correct.

Census block ID: 480019501001
total population: 1,437
area: 1824095459 In UNKNOWN units
population density: 22.5 In UNKNOWN units

The calculation for population density $\displaystyle \frac{TotalPopulation}{Area}$. Population density is usually in KM or Miles.

I am assuming 1824095459 is in square feet, because anything else wouldn't make sense.

So converting 1824095459 ft to miles = 1824095459/5280= plug into population density equation = .004159519 Population density of people per mile

converting 1824085459 ft to KM = 1824095459/3280.8399= plug into population density equation = .002584605 Population density of people per KM

Neither one of these answers is the 22.5 in unknown units figure they listed as the answer for this block group.

Where did I/they make the mistake?
• Oct 23rd 2009, 07:33 AM
masters
Quote:

Originally Posted by allyourbass2212
Basically I downloaded some information from that lists population density per a census block group, but their population density calculation doesn't seem to be correct.

Census block ID: 480019501001
total population: 1,437
area: 1824095459 In UNKNOWN units
population density: 22.5 In UNKNOWN units

The calculation for population density $\displaystyle \frac{TotalPopulation}{Area}$. Population density is usually in KM or Miles.

I am assuming 1824095459 is in square feet, because anything else wouldn't make sense.

So converting 1824095459 ft to miles = 1824095459/5280= plug into population density equation = .004159519 Population density of people per mile

converting 1824085459 ft to KM = 1824095459/3280.8399= plug into population density equation = .002584605 Population density of people per KM

Neither one of these answers is the 22.5 in unknown units figure they listed as the answer for this block group.

Where did I/they make the mistake?

Hi allyourbass2212,

To convert square feet to square miles:

$\displaystyle 1824095459 \cdot \frac{1 \ \ mi^2}{5280^2}=65.4 \ \ mi^2$

But, that doesn't give you the right density.

$\displaystyle \frac{1437}{65.4}=21.9$

Similiarly, 1824095459 square feet = 169.5 square km.

That yields a density of about 8.5.

So, I don't know. You might work with square meters and see what happens.
• Oct 23rd 2009, 09:19 AM
allyourbass2212
I suppose my original calculation was incorrect because I did it for ft and not square ft?
• Oct 23rd 2009, 09:50 AM
masters
Quote:

Originally Posted by allyourbass2212
I suppose my original calculation was incorrect because I did it for ft and not square ft?

Yes, you have to divide 1824095459 by $\displaystyle 5280^2$.

Here's a converter for you: CalculateMe.com - Convert Square Feet to Square Miles