#include <bits/stdc++.h>
using namespace std;

int main(){
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    
    int t;
    cin >> t;
    while(t--){
        int n;
        cin >> n;
        vector<long long> a(n+1, 0);
        for(int i=1;i<=n;i++) cin >> a[i];
        
        // Compute left[i]: length of strictly decreasing sequence ending at i
        vector<int> left(n+1, 1);
        for(int i=2;i<=n;i++){
            if(a[i-1] > a[i]){
                left[i] = left[i-1] +1;
            }
            else{
                left[i] =1;
            }
        }
        
        // Compute right[i]: length of strictly increasing sequence starting at i
        vector<int> right(n+1,1);
        for(int i=n-1;i>=1;i--){
            if(a[i] < a[i+1]){
                right[i] = right[i+1] +1;
            }
            else{
                right[i] =1;
            }
        }
        
        // Compute prefix_sum
        vector<long long> prefix_sum(n+1, 0);
        for(int i=1;i<=n;i++) prefix_sum[i] = prefix_sum[i-1] + a[i];
        
        double max_avg = -1e18; // Initialize to a very small number
        for(int i=1;i<=n;i++){
            if(left[i] >=2 && right[i] >=2){
                int L = i - left[i] +1;
                int R = i + right[i] -1;
                if(L <1) L=1;
                if(R >n) R=n;
                // Ensure that [L, R] is a V-diagram
                // Since left and right arrays ensure that up to i it's decreasing and from i it's increasing
                // Thus, [L, R] is a V-diagram
                long long sum = prefix_sum[R] - prefix_sum[L-1];
                int len = R - L +1;
                double avg = (double)sum / len;
                if(avg > max_avg){
                    max_avg = avg;
                }
            }
        }
        // Print with 12 decimal digits
        cout << fixed << setprecision(12) << max_avg << "\n";
    }
    return 0;
}