Would like to get expert opinion on sample size calculation.
I am planning to conduct case control study.
Followings are my study detail.
Aim: to compare the effectiveness of air filter by measuring the fungal spore count in the rooms
Hypothesis: rooms with filter should have low spore count than rooms without filter
case: room with filter
control: room without filter
To get statistically significant results with appropriate power, how many sample we need to get?
I have read some literature and found out
The incident rate in rooms with filter was 17.51
whereas rooms without filter was 34.61
Incidet rate ratio was 1.98
Odd ratio was 0.49
I tried to calculate sample size by using power and sample size calculation software.
The result show me i need 136 cases and 136 controls to get 0.8 power and 0.05 alpha.
I would like to validate my result whether the way of calculation is correct.
Really appreciate if you can advise me.
Thanks much in advance.
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