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## Topic review (newest first)

bob bundy
2013-04-07 04:44:57

Yes that's the weight that is needed.

If you weren't given them, you'll have to look them up.

simple example to show why you have to do this.

Suppose country A has 1000 people and 100 are unemployed.  That's 10% unemployed.

Suppose country B has 10 people and 9 are unemployed.  That's 90% unemployed.

If you just do (10 + 90)/2 = 50, you've given too much importance to country B

You need to go back to the raw data.

Total population = 1000 + 10 = 1010
Total unemployed = 109.

So true average = 109/1010 x 100 = 10.8%

The answer is properly weighted towards the larger population.

Using the formula {(1000 x 10) + (10 x 90)} / 1010 = 10.8

Bob

bobbym
2013-04-07 04:40:10

Maybe they want you to look up the populations of the countries.

clueless101
2013-04-07 04:38:51

They do mention that the weights are necessary since the populations of the countries are different. If they were all equal the average would be the sum of all percentages divided by 14.

other than that it's just the country names which I left out

bobbym
2013-04-07 04:25:55

Hi;

That is the entire question? You are sure you have not left anything out?

clueless101
2013-04-07 04:23:34

The book only gives me the country names and the unemployment rates

btw thanks guys for your time

gAr
2013-04-07 04:15:33

Hi clueless101,

There must be another column for weights, by default we take weight to be 1 for each country.

We get 104.2 / 14 = 7.44285714286

bobbym
2013-04-07 04:10:45

I do not think you are providing everything. Where are the weights?

You will need them to get 8.2

clueless101
2013-04-07 04:09:32

I have been trying that, but not getting to 8.2

Agnishom
2013-04-07 03:56:23

just add 'em up and divide by 14

clueless101
2013-04-07 03:53:21

Hey there
The  unemployment rate of the 14 countries are the following:

4.0
7.2
6.8
6.6
8.3
7.8
7.8
9.6
6.7
5.1
3.9
7.8
7.8
14.8

Weighted Average is 8.2%
How did they get this 8.2??

Agnishom
2013-04-07 03:42:48

Weighted Average of the countries = ((Frequency 1)*(Rate 1) + (Frequency 2)*(Rate 2) + ...)/14

Maybe I need to know more about the problem

bobbym
2013-04-07 03:41:05

Hi;

Weighted really just means multiplying the data by constants. What are you taking an average of? Do you have some data?

clueless101
2013-04-07 03:38:06

How would you find the weighted average of example 14 different countries with different unemployment rates?