#include <bits/stdc++.h>
#define all(x) (x).begin(), (x).end()
using namespace std;
typedef long long ll;
typedef long double ld;
const int mod = 1e9 + 7;
const int N = 1e6 + 5;

void solve() {
	int n; cin >> n;
	vector<int> a(n), b(n), c(n);
	for (int i = 0; i < n; i++)
		cin >> a[i];
	ll sm = 0;
	ld lo = 1, hi = 1e9;
	for (int i = 0, j = -1, f = 0; i < n; i++) {
		sm += a[i];
		if (i > 0) {
			b[i] = max(b[i - 1], i);
			c[i] = max(c[i - 1], i);
		}
		while (b[i] + 1 < n && a[b[i]] >= a[b[i] + 1])
			b[i]++;
		while (c[i] + 1 < n && a[c[i]] <= a[c[i] + 1])
			c[i]++;
		if (i > c[0] && i > b[c[0] + 1])
			lo = max(lo, sm / ld(i + 1));
	}
	for (int it = 0; it < 100; it++) {
		ld mi = (lo + hi) / 2, pref = 0;
		int ok = 0;
		vector<pair<ld,int>> arr;
		for (int i = 0; !ok && i < n; i++) {
			pref += a[i] - mi;
			int j = lower_bound(arr.begin(), arr.end(), make_pair(pref, n), greater<pair<ld,int>>()) - arr.begin();
			if (j < size(arr) && i > c[arr[j].second] && i > b[c[arr[j].second]])
				ok = 1;
			if (arr.empty() || pref < arr.back().first)
				arr.push_back(make_pair(pref, i));
		}
		if (ok == 1)
			lo = mi;
		else
			hi = mi;
	}
	cout << fixed << setprecision(10) << lo << "\n";
}

int main() {
	ios_base::sync_with_stdio(false); cin.tie(0);
	int t; cin >> t; while (t--) solve();
}