R/t.sample.sistematica.R

In mleal93/t.sample: Sample Techiniques

  	#'
	#' @title Sistematic Sampling
	#' @description A function that returns the results from calculated estimated values for Sistematic Sampling.
	#'
	#' @import stats
	#' @param data A data frame.
	#' @param c.lev Confidence Level.
	#' @param N Size of population.
	#' @param type Put "p" for estimate values for proportion.
	#' @param c.unit TRUE if want to transpose data frame.
	#'
	#' @author Marco Aurelio Valles Leal
	#'
	#' @export


	smp.sistematica = function(data=NULL,c.lev=95,N=NULL,type=NULL,c.unit=NULL,n=NULL,k=NULL,pi=NULL,np=NULL) {
  if (is.null(type)){
	    n=length(data[,1])
	    ni=apply(data,2,length)
	    k=length((data[1,]))
	    x_barra=apply(data,2,mean,na.rm=T)
	    s=apply(data,2,sd,na.rm=T)
	    y_barra=mean(x_barra)
	    v_ybarra=(1/N)*sum((x_barra-y_barra)^2*ni)
	    ep=sqrt(v_ybarra)

	    if(TRUE){statistic.val     =qt(p=.5+c.lev/200, df = n-1 );statistic="t Student Statistic"}
	    else {statistic.val = qnorm(.5+c.lev/200);statistic="Score Statistic (Z)"}
	    confidence.interval.ybarra   =round(y_barra+(c(-1,1)*statistic.val*(ep)),6)




	    METHOD = paste("Results for calculated estimatives for Cluster Sampling (Proportion)")
	    structure(list(
	      "Statistic                    "    = statistic,
	      "Statistic Value              "    = statistic.val,
	      "Groups  (k)                  "    = k,
	      "Sample Size (n)              "    = n,
	      "Population Size (N)          "    = N,
	      "Mean                         "    = x_barra,
	      "Y_barra                      "    = y_barra,
	      "Sd                           "    = s,
	      "Var                          "    = s^2,
	      "V(y_barra)                   "    = v_ybarra,
	      "EP                           "     = ep,
	      "Confidence Interval of y_bar2"    = paste0("IC",c.lev,"% : [ ",confidence.interval.ybarra[1]," ; ",confidence.interval.ybarra[2]," ]"),

	      method=METHOD
	    ),class = "power.htest")
  }else{
   
    statistic.val = qnorm(.5+c.lev/200);statistic="Score Statistic (Z)"
    p=np/N
    q=1-p
    V_ybarra=(((N-n)/(N-1))*((p*q)/n))
	  V_sist=sum((pi - p)^2)/k
	  ep=sqrt(V_sist)
	  ic= round(p+(c(-1,1)*statistic.val*(ep)),6)
	  cat("V_ybarra(AAS): ",V_ybarra,"\n\n",
	      "V_sistematica: ",V_sist,"\n\n",
	      "EP: ",ep,"\n\n",
	      "IC : [",ic[1],";",ic[2],"]"
	      )

}

	}