#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
const int N = 3e5 + 5;
int a[N];
ll sum[N];

void solve() {
	int n;
	cin >> n;
	int id = -1;
	for (int i = 1; i <= n; i++) {
		cin >> a[i];
		sum[i] = sum[i - 1] + a[i];
	}
	for (int i = 2 ; i < n ; i++) {
		if (a[i] < a[i - 1] && a[i] < a[i + 1]) {
			id = i;
		}
	}
	long double c1 = 1.0 * sum[n] / n;
	long double c2 = 1.0 * (sum[n] - sum[id - 2]) / (n - (id - 2));
	long double c3 = 1.0 * sum[id + 1] / (id + 1);

	cout << fixed << setprecision(18) << max({c1, c2, c3}) << '\n';
}

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