Hi everyone,

I got a basic question I can't quite wrap my head around.

The following values for occurrences from a table:

Group 1 average 60% (n=150 from 250 cases)

Group 2 average 53.93% (n=192 out of 356 valid cases)

Total average is ~

As there are different sample sizes, weighted average applies which however is =

What am I missing? Where is the .2 difference coming from? As I gather it, they should be exactly the same, with the weighted average having the advantage not to be dependent of the number of cases/totals, being calculated just with in-group occurrences times means.

Thanks,

statcat

I got a basic question I can't quite wrap my head around.

The following values for occurrences from a table:

Group 1 average 60% (n=150 from 250 cases)

Group 2 average 53.93% (n=192 out of 356 valid cases)

Total average is ~

**56.4%**(n=342 of 606)As there are different sample sizes, weighted average applies which however is =

**56.59**What am I missing? Where is the .2 difference coming from? As I gather it, they should be exactly the same, with the weighted average having the advantage not to be dependent of the number of cases/totals, being calculated just with in-group occurrences times means.

Thanks,

statcat

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