When a manual trap is checked, the number of moths found is the total accumulation since the last check. For example, if I check a trap on Monday and then again on Friday, the moths I count on Friday were caught on Tuesday, Wednesday, Thursday, and/or Friday. Since we cannot know which day the moths were caught, the system assigns the average number of moths to each day. So if I count 6 moths on Friday and the last check was Monday, it would assign 6 / 4 = 1.5 moths to each day for Tuesday through Friday.
Moths per day:
Moths per trap per day:
Trapping is a random sampling of the insect population and there can be large variations in the number of insects because of this even if the underlying population is the same. Averaging the trap counts across a field reduces the impact of random variation and can result in a more accurate estimate of the underlying population. The average is computed per day based on the moths per day calculation above. Note that the first count a trap receives is averaged over the last 7 days (inclusive of the day of) since we don't have a previously checked date to go off.
* per week:
When the graph is in week view, the moths per day for each day in the week are added together and the result is shown. It adds each individual trap's daily average for the week, but does still average those sums across the traps involved on the graph. Weeks are currently defined as Sunday - Saturday.
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