#include<bits/stdc++.h>
using namespace std;
#define ll long long 
const int N = 1e6+9;
int T,n;
long long a[N],sum[N];



int main(){
    scanf("%d",&T);
    while(T--){
        scanf("%d",&n);
        for(int i=1;i<=n;i++) scanf("%lld",&a[i]);
        for(int i=1;i<=n;i++)
            sum[i]=sum[i-1]+a[i];        
        int pos=0;
        for(int i=1;i<=n;i++)
            if(a[i]<a[i-1]&&a[i]<a[i+1]) pos=i;
        double ans=(double)sum[n]/(double)n;
        ans=max(ans,(double)(sum[n]-sum[pos-2])/(double)(n-pos+2));
        ans=max(ans,(double)sum[pos+1]/(double)(pos+1));
        printf("%.15lf\n",ans);
    }



    return 0;
}