# Randomly selects two stations and estimates power and effsize. 100 independent draws  

rm(list=ls())

 library(compute.es)

f0= read.table("R & rt Prev & CI.txt", header=T)

pow= numeric(4); a1=numeric(4); size= numeric(4); diff=numeric(4); poder=numeric(4); efsize=numeric(4)
f3= data.frame(size, diff, poder, efsize)
  lb= c("10x1", "10x2",  "25x2", "50x2")

for (j in 1:100) {
 for (i in seq_along(lb)) { # select two samples per each belt-transect dimension 
  t1= f0[f0$size %in% lb[i],]
  t2= t1[sample(nrow(t1),2),]
    size[i]= lb[i]     
   diff[i]= abs(t2[1,3] - t2[2,3]) # Difference in colony abundance
  pp= power.prop.test(n = t2[1,3] + t2[2,3], p1 = t2[1,4], p2 = t2[2,4]) #achieved power
    pow[i]= round(pp$power,2)

 a= propes(p1= t2[1,4], p2= t2[2,4], 100, 100, verbose= F)
   a1[i]= round(abs(a$cliffs.d),2)# effect size 
     }
  f2= data.frame(size= unlist(size), diff= unlist(diff), poder= unlist(pow), efsize= unlist(a1))
  f3= rbind(f3, f2)
}

f3= f3[-c(1:4),]
  
write.table(f3, "power & efsize DATA.txt", quote=F, sep=" ", row.names=F)