What you can say for sure, is that it is unlikely that the half-life is > 1 s. You could estimate an upper limit.
What you need to clarify is 'why do you want to know?' Then you need to establish what information do you need to answer 'why' and what are the criteria for accepting the answer.
You should find that the investigation as described in your question needs a major redesign. A major part of the redesign is 'do the calculations and statistics first.'