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

int t, n, center;
ll a[300005];
ll temp, minA;

int main() {
    ios::sync_with_stdio(0), cin.tie(0);
    cin >> t;
    while(t--) {
        cin >> n;
        minA = 1000000005;
        for (int i = 0; i < n; i++) {
            cin >> temp;
            a[i] = temp;
            if (a[i] < minA) {
                minA = a[i];
                center = i;
            }
        }

        ll leftSum = a[center + 1];
        ll rightSum = a[center - 1];

        for (int i = center; i >= 0; i--) {
            leftSum += a[i];
        }
        
        for (int i = center; i < n; i++) {
            rightSum += a[i];
        }

        double leftAvg =  1.0 * leftSum / (center + 2);
        double rightAvg = 1.0 * rightSum / (n - center + 2);

        if (leftAvg > rightAvg) {
            ll tempSum = leftSum;
            ll cnt = center + 2;
            double tempAvg = 0;

            for (int i = center + 2; i < n; i++) {
                tempSum += a[i];
                cnt++;
                tempAvg = 1.0 * tempSum / cnt;
                if (tempAvg > leftAvg) {
                    leftAvg = tempAvg;
                }    
            }

            cout << fixed;
            cout.precision(10);
            cout << leftAvg << "\n";
        } else { 
            ll tempSum = rightSum;
            ll cnt = n - center + 2;
            double tempAvg = 0;

            for (int i = center - 2; i >= 0; i--) {
                tempSum += a[i];
                cnt++;
                tempAvg = 1.0 * tempSum / cnt;
                if (tempAvg > rightAvg) {
                    rightAvg = tempAvg;
                }    
            }

            cout << fixed;
            cout.precision(10);
            cout << rightAvg << "\n";
        }
    }

    return 0;
}