mean_R = mean(RFM.df$R)
mean_F = mean(RFM.df$F)
mean_M = mean(RFM.df$M)
for(i in 1:nrow(RFM.df)){
  if(RFM.df[i,"R"]>=mean_R & RFM.df[i,"F"]>=mean_F & RFM.df[i,"M"]>=meam_M){
    RFM.df$group[i] = 1
  }
  if(RFM.df[i,"R"]<mean_R & RFM.df[i,"F"]>=mean_F & RFM.df[i,"M"]>=meam_M){
    RFM.df$group[i] = 2
  }
  if(RFM.df[i,"R"]>=mean_R & RFM.df[i,"F"]>=mean_F & RFM.df[i,"M"]<meam_M){
    RFM.df$group[i] = 3
  }
  if(RFM.df[i,"R"]>=mean_R & RFM.df[i,"F"]<mean_F & RFM.df[i,"M"]>=meam_M){
    RFM.df$group[i] = 4
  }
  if(RFM.df[i,"R"]<mean_R & RFM.df[i,"F"]>=mean_F & RFM.df[i,"M"]<meam_M){
    RFM.df$group[i] = 5
  }
  if(RFM.df[i,"R"]>=mean_R & RFM.df[i,"F"]<mean_F & RFM.df[i,"M"]<meam_M){
    RFM.df$group[i] = 6
  }
  if(RFM.df[i,"R"]<mean_R & RFM.df[i,"F"]<mean_F & RFM.df[i,"M"]>=meam_M){
    RFM.df$group[i] = 7
  }
  if(RFM.df[i,"R"]<mean_R & RFM.df[i,"F"]<mean_F & RFM.df[i,"M"]<meam_M){
    RFM.df$group[i] = 8
  }
}