Trying to Calculate Averages for Record Types

Question

I am trying to compute the averages for the following (3) types of records but not sure if I am getting the correct results:

387 Total record count (valid/invalid/other) - created by 45 total users 94 of these records are valid - created by 5 different users 65 of these records are invalid - created by 10 different users 228 of these records are other - created by 30 different users

Average number of valid records - 387 / 94 = 4.11 Average number of invalid records - 387 / 65 = 5.95 Average number of other records - 387 / 228 = 1.69

Should the denominator value be the sum of each record type (94, 65, 228), the sum of all the records (387) or the sum of users for each record type (5, 10, 30)?

Thank you.

Answer 1

If you are talking about the average that everyone understands, then this is how to compute it, following your data:

Total records: $$ 94 + 65 + 228 = 387$$ Valid records average: $$\frac{94}{387}\times 100 \approx 24\%$$ Invalid records average: $$\frac{65}{387}\times 100 \approx 17\%$$ Other records average: $$\frac{228}{387}\times 100 \approx 59\%$$

Answer 2

You need to carefully say what you are calculating. If you want the average number of valid records created by a user who has created at least one valid record, it is $\frac {387}{94} \approx 4.11$ What denominator you use depends on what you want to calculate. You might want to calculate the average number of valid records created by any of your users. If the three groups of users are disjoint (do you know if they are?) that would be $\frac {387}{94+5+30}$. Which of these numbers is more useful depends on what you want to do with the number. There is no one average that is correct-there is a correct way to compute an average that you specify.