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Topic: Weighted Averages (Question)
Replies: 1   Last Post: Dec 1, 2004 12:31 AM

 Messages: [ Previous | Next ]
 Julie Posts: 9 Registered: 1/25/05
Weighted Averages (Question)
Posted: Nov 29, 2004 3:35 PM

Hello, I was having a bit of trouble understanding something with
weighted averages. Suppose I have the following formula for per-pupil
revenue in a given state: Total Revenue (in a given state)/Average
Daily Attendance (in a given state). Now if I want to find the average
per-pupil revenue across the whole U.S. wouldn't I take the sum of all
total revenues in the U.S.(sum each of the 50 states) and divide that
by the sum of all Average Daily Attendance figures in the U.S. (sum
each of the 50 states)?? Wouldn't this be a weighted average of
per-pupil revenue that is more accurate than taking the sum of all
total revenues and dividing by the number of states?? I'm just having
problems relating this calculation to the basic weighted average
formula (sum of weight*quanitities/sum of quantities). Is the "weight"
in my calculation the Average Daily Attendance??

Similarly, suppose the formula for Average Daily Attendance (for a
given state)= aggregate number of days pupils (in a given state)
attend class/total number of days in school year (for a given state).
If I want a national average for average daily attendance, rather than
summing the Average Daily Attendance for each state and dividing by
50, would I sum the aggregate number of days pupils attend class in
each state and divide by the cumulative number of days in a school
year for all states? Is this correct and would this be considered a
weighted average?? Would the weight be the total number of days in a
school year (for a given state)?? Again, I am having problems seeing
how the basic weighted average formula applies to this calculation.

Another problem I anticipate having is that not all states use the
above formula for average daily attendance (i.e. some have complex
formulas incorporating summer school students, actual number of hours
students attended class rather than number of days, etc.) In this
case, would simply taking the sum of Average Daily Attendance and
dividing by number of states be the best way to calculate Average
Daily Attendance or is there another weighted mean that is
preferable?? Thanks for any insight!!!

Juile

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Date Subject Author
11/29/04 Julie
12/1/04 Brian Harvey