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

// #define int long long

const int N = 2e5 + 10; 


void solve()
{
	int n;
    cin >> n;
    vector<int> a(n + 5);

    int p = 0;
    int sum = 0;
    for(int i = 1; i <= n; i ++ )
    {
        cin >> a[i];
        sum += a[i];
    }
    for(int i = 2; i <= n; i ++ )
    {
        if(a[i] > a[i - 1]) break;
        p = i;
    }
    // cout << p << endl;

    int l = 1, r = n;
    double s1 = sum, a1 = 1.0 * sum / n;
    for(int i = 1; i < p - 1; i ++ )
    {
        s1 -= a[i];
        double tmp = 1.0 * s1 / (n - i);
        if(tmp > a1)
        {
            a1 = max(a1, tmp);
        }
    }
    double s2 = sum, a2 = 1.0 * sum / n;
    for(int i = n; i > p + 1; i -- )
    {
        s2 -= a[i];
        double tmp = 1.0 * s2 / (i - 1);
        if(tmp > a2)
        {
            a2 = max(a2, tmp);
        }
    }
    // cout << a1 << ' ' << a2 << endl;
    double ans = max(a1, a2);
    cout << fixed << setprecision(12) << ans << endl;
}

signed main()
{
	ios::sync_with_stdio(0);
	cin.tie(0), cout.tie(0);
	
	int t = 1; 
	cin >> t; 
	while(t -- )
	{
		solve();
	}
	
	return 0; 
}