[R] What is best way to calculate % of time?

[Neotropical bat risk assessments]

Hi Bert,

Tnx for taking time to reply.
For clarification... the data do EXPLICITLY indicate when each species 
is active and when a feeding buzz is recorded.
That is ALL it provides based on acoustic data recorded in the field.  
Only when a species is recorded  is it identified as active.
How this is accomplished is of no importance to the question I asked.

Note this is Not "individuals" per se. but species as a group.

I appreciate you taking time to reply.
Clearly this is not a simple solution to what I assumed to be a simple 
question.
Restated as...
*How best to use R to calculate occurrence of event( (A) over time vs 
all events (b...n) over the same time period give the data frame work I 
have.*

Cheers,
Bruce


> I will not get into your explanation of details that, like John, I 
> find opaque. Please DO read Hadley's manifesto, as it appears that you 
> need to organize your data more appropriately.
>
> AFAICS, however, strictly speaking your data cannot answer the 
> question you have posed. **Strictly speaking** to know the proportion 
> of active time bats spend feeding, **for each bat** you would need to 
> know when it is active and when it is feeding during that time. You 
> could then summarize this for all bats (e.g. take the average or 
> median proportion) in a species or whatever. As you cannot identify 
> individual bats in your data, you cannot do this -- i.e. you cannot 
> answer your question.
>
> So the question then becomes: precisely **how** exactly do you propose 
> using the data you have to determine when a *group* of bats are active 
> and when they are feeding? How are the groups explicitly identified 
> and how are their times active and feeding determined? In short, you 
> need to have information that is something like:
>
> Bat.Group date   active.time.start  active.time.end  
> feeding.time.start feeding.time.end
>
> ( for a given date and bat group, there may be many multiple entries; 
> perhaps for a given group, date, and active time start and end, 
> several feeding time start/stop entries ( I have no idea how bats 
> behave)).
>
> Until you can expicitly explain how your data can generate such 
> information, I think it will be difficult/impossible to help you.
>
> Cheers,
> Bert
>

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