[R-sig-eco] Reshape or Plyr?

[Baldwin, Jim -FS]

Shouldn't the analysis account for the different lengths of time?  Why standardize and (I assume) effectively ignore the differences in lengths of time?  Is there an "offset" feature in the proposed analysis as in lm and glmer that could be used?

Jim


-----Original Message-----
From: r-sig-ecology-bounces at r-project.org [mailto:r-sig-ecology-bounces at r-project.org] On Behalf Of Bruce Miller
Sent: Saturday, April 20, 2013 3:43 AM
To: r-sig-ecology at r-project.org
Subject: [R-sig-eco] Reshape or Plyr?

H all,

I have relative abundance data from >100 sites.  This is from acoustic monitoring and usually the data is for 2-3 nights but in some cases my be longer like months for each location..
The data output from  my management data base is proved by species by night for each location so data frame would look like this below.  What I need to do is sum the Survey_time by Spec_Code for each location name and divide summed AI values for each Spec_code by the summed Survey time to adjust for unit effort then standardize it all by *10 to represent the relative abundance by survey hour to 10 hours. How best to do this?
Using Plyr or reshape?

Location name   SPEC_CODE       Start_Day       Survey_Time     AI      Std AI
079-f2p1-Acetuna        Buzz    2/14/2012       12.1    1       0.8264463
079-f2p1-Acetuna        Buzz    2/14/2012       12.1    1       0.8264463
079-f2p1-Acetuna        Eumspp  2/14/2012       12.1    1       0.8264463
079-f2p1-Acetuna        Frag    2/14/2012       12.1    18      14.87603
079-f2p1-Acetuna        Molspp  2/14/2012       12.1    5       4.132231
079-f2p1-Acetuna        Molspp  2/14/2012       12.1    5       4.132231
079-f2p1-Acetuna        Phyllo  2/14/2012       12.1    2       1.652893
079-f2p1-Acetuna        Ptedav  2/14/2012       12.1    1       0.8264463
079-f2p1-Acetuna        Ptegym  2/14/2012       12.1    1       0.8264463
079-f2p1-Acetuna        Ptepar  2/14/2012       12.1    2       1.652893
079-f2p1-Acetuna        Rhotum  2/14/2012       12.1    6       4.958678
079-f2p1-Acetuna        Sacbil  2/14/2012       12.1    6       4.958678
079-f2p1-Acetuna        Saclep  2/14/2012       12.1    11      9.090909
079-f2p1-Acetuna        Buzz    2/15/2012       12.1    2       1.652893
079-f2p1-Acetuna        Buzz    2/15/2012       12.1    2       1.652893
079-f2p1-Acetuna        Molmol  2/15/2012       12.1    1       0.8264463
079-f2p1-Acetuna        Molspp  2/15/2012       12.1    7       5.785124
079-f2p1-Acetuna        Molspp  2/15/2012       12.1    7       5.785124
079-f2p1-Acetuna        Nocalb  2/15/2012       12.1    6       4.958678
079-f2p1-Acetuna        Phyllo  2/15/2012       12.1    1       0.8264463
079-f2p1-Acetuna        Ptedav  2/15/2012       12.1    1       0.8264463
079-f2p1-Acetuna        Ptegym  2/15/2012       12.1    4       3.305785
079-f2p1-Acetuna        Ptepar  2/15/2012       12.1    4       3.305785
079-f2p1-Acetuna        Pteper  2/15/2012       12.1    3       2.479339
079-f2p1-Acetuna        Rhotum  2/15/2012       12.1    7       5.785124
079-f2p1-Acetuna        Sacbil  2/15/2012       12.1    2       1.652893
079-f2p1-Acetuna        Saclep  2/15/2012       12.1    6       4.958678
079-f2p1-Acetuna        Buzz    2/16/2012       12.2    1       0.8196721
079-f2p1-Acetuna        Buzz    2/16/2012       12.2    1       0.8196721
079-f2p1-Acetuna        Eumspp  2/16/2012       12.2    4       3.278688
079-f2p1-Acetuna        Molspp  2/16/2012       12.2    2       1.639344
079-f2p1-Acetuna        Molspp  2/16/2012       12.2    2       1.639344
079-f2p1-Acetuna        Myokea  2/16/2012       12.2    1       0.8196721
079-f2p1-Acetuna        Nocalb  2/16/2012       12.2    4       3.278688
079-f2p1-Acetuna        Phyllo  2/16/2012       12.2    1       0.8196721
079-f2p1-Acetuna        Ptedav  2/16/2012       12.2    1       0.8196721
079-f2p1-Acetuna        Ptegym  2/16/2012       12.2    1       0.8196721
079-f2p1-Acetuna        Ptepar  2/16/2012       12.2    3       2.459016
079-f2p1-Acetuna        Pteper  2/16/2012       12.2    1       0.8196721
079-f2p1-Acetuna        Rhotum  2/16/2012       12.2    17      13.93443
079-f2p1-Acetuna        Sacbil  2/16/2012       12.2    3       2.459016
079-f2p1-Acetuna        Saclep  2/16/2012       12.2    15      12.29508


Thanks for any suggestions.  Excel will be a mess to try to do that.

Bruce

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