# sample size

#### bell

##### New Member
Hey all
i have two age group to study on the same area, but will ask them completely different questions using different tools. here is the population

Age, male, female, total
2-5, 7500, 7500, 15000
6-8, 9000, 9000, 18000

So when i calculate the sample size do i use 33,000 the total population or each age group population. remember the questionnaires for each age is on different topics
thank you

#### hlsmith

##### Less is more. Stay pure. Stay poor.
What is the question you are trying to answer with the sample size calculation?

#### bell

##### New Member
for both age group the question i am trying to answer is different for example for the 1st age group it is whether they are overweight , underweight , vaccinated and also if they were taking any food supplement in the previous months. For the 2nd age group what i am trying to answer is whether they are attending school regularly, treated well at school, or get sick very often. hope this help and thank you again

#### Karabiner

##### TS Contributor
Still not sure what you are trying to answer. Do you want to compare sample data with your "population" data?
Or, do you want to compare are sample of males with a sample of females? And why do you need to consider
"population" size - do you need to perform a correction for finite populations?

Anyway, if you perform 2 completely separated analyses, why should sample size considerations for one analysis be
affected by the other Analysis?

With kind regards

Karabiner

#### bell

##### New Member
Thank you very much Karabiner
Agree I think my question were not that clear. Let me try to simplify it again
i have 3 small town to study with a limited budget and the population i want to study is as follows:

Town....Age 2 to 5.....Age 6 to 8.....Total....Sample Size calculated
A.............15000...........18000...............33000................380
B................5500.............5000...............10500.................371
C ...............9600..............9000..............18600................377
Total for 3 towns.................................62100

I calculated the above sample size for each town based on 95 CI and 5% Margin of error. My question is do i take the sample size above for each town and spread it proportionally to each age group or calculate the sample size for 62,000 which is 382? What i want to make sure is that if i take each town sample size the total sample size will be around 1128 which is Big (needs \$ which i do not have) and if i take the 382 and spread it proportionally to the age group and town it becomes small.

The question i want to answer for each group is completely different and i am not comparing the group at all . i have developed a questions for those 2 to 5 and want to know how many of them are underweight, overweight or taking food supplement . For the 2nd age group i have a different questionnaire which i just want to see if they are attending primary school regularly.

I hope i am making sense

Thank you again all