#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
constexpr int N = 1e5 + 5;
int n, a[N];
ll sum[N];
signed main()
{
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
    int tt = 1;
    cin >> tt;
    while (tt--)
    {
        int n, pos;
        cin >> n;
        sum[0] = 0;
        int mn = INT_MAX;
        for (int i = 1; i <= n; i++)
        {
            cin >> a[i];
            if (a[i] < mn)
            {
                mn = a[i];
                pos = i;
            }
            sum[i] = sum[i - 1] + a[i];
        }
        long double mx = 0.0;
        mx = max({(long double) 1.0 * (sum[n] - sum[0]) / n, (long double) 1.0 * (sum[pos + 1] - sum[0]) / (pos + 1),
                  (long double) 1.0 * (sum[n] - sum[pos - 2]) / (n - pos + 2)});
        cout << mx << '\n';
    }
    return 0;
}