search for: spec_cod

...toring and usually the data is for 2-3 nights but in some cases my be longer like months or years 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...