#! /usr/bin/gawk -f
BEGIN{
FS=",";
k=0;
}

i<=150 && NR>0{

#caluculate the new mean old mean,stdDev

#print NR
era+=log($1);
train[NR]+=log($1);
trainMean[NR]=train[NR]/NR
trainSumS= (log($1)-trainMean[NR])*(log($1)-trainMean[NR])
#itraindev[NR]=trainSumS[NR]/NR
i++
if((NR)%150==0)
{
i=0;
d[instant_count]=NR;
eraMean[instant_count]=era/150;
eraDev[instant_count]=(trainSumS/150);
#print instant_count
#instant_count++;
if((z=Ztest(eraMean[instant_count],trainMean[NR],eraDev[instant_count],NR))<-4.2645)
{
print z
#check for stability for 3  era and note down the first one print NR
#print instant_count 
}
instant_count++ 
era=0
trianSumS=0;
}
d[instant_count]=NR
}

END{

#for(i in trainMean)
#print i "\t" trainMean[i] "\t" train[i] "\t" traindev[i]
for (k in eraMean)
{
print d[k] "\t"  eraMean[k]}
}

function Ztest(newMean,oldMean,stDev,totInst){
    if(stDev == 0) return newMean - oldMean;
    return (newMean-oldMean)/(stDev/sqrt(totInst));
  }