I have been asked to compile a report into dropout rates during checkout for a global webstore
I have used a sample size over one month as my sample because:
- google analytics slows to a crawl over larger sample sizes and makes much of the analysis agonisingly slow
- I believe it to be statistically significant and a representative sample
My client has asked me why I didn't use yearly figures and wants proof that one month of data is 'statistically significant'.
Am I right in thinking that I need to compare the standard deviation of my monthly sample to the yearly sample and ensure that the deviation is under a certain %age?
Question: how do I prove one month of Google Analytics data is representative to one year worth of data?
- 90k unique views/month
- ~1.1m per year.