I want to experiment with a change to a financial transaction limit. The focus of the experiment will be the change of loss per at-risk transaction. I want to calculate the sample size required to detect a given effect size.
I know very little about statistics, so I’m not sure where to start with this. I think these are the important/relevant details:
- There are very few at-risk transactions. ~19 monthly average for the last 5 months.
- Loss is infrequent. 0.8% of at-risk amount per month, arising from 2 events in the last 5 months.
I want to know when a larger loss in the experimental group will be attributable to a change in the limit. I don’t know what method(s) to use here.