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Question: Does the rate of arrival differ across two time periods?

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# events # days Confidence interval (arrival rate)
Sample 1: /
12.230.9
Sample 2: /
16.236.9
Verdict:
No
(p = 0.21)
Confidence level:
95%

If the experiment is repeated many times, the confidence level is the percent of the time each sample's arrival rate will fall within the reported confidence interval.

It is also the percent of the time no difference will be detected between the two groups, assuming no difference exists.

If you like this, check out Wizard — the easy Mac statistics app.