#include <bits/stdc++.h>
using i64 = long long;

void solve() 
{
	int n;
	std::cin >> n;
	std::vector<int> a(n + 1);
	std::vector<int64_t> pre(n + 1);
	for(int i = 1; i <= n; ++i) 
	{
		std::cin >> a[i];
		pre[i] = pre[i - 1] + a[i];
	}
	int L = 1, R = n;
	auto findl = [&](int l) ->int {
		while(l + 1 <= R) {
			if(a[l] > a[l + 1]) break;
			l++;
		}
		return l;
	};
	auto findr = [&](int r) ->int {
		while(L <= r - 1) {
			if(a[r] > a[r - 1]) break;
			r--;
		}
		return r;
	};
	L = findl(L), R = findr(R);
	auto cmp = [&](int l, int r, int nl, int nr) ->bool {
		return __int128(pre[r] - pre[l - 1]) * __int128(nr - nl + 1) 
			<= __int128(pre[nr] - pre[nl - 1]) * __int128(r - l + 1);
	};
	while(true) {
		int l = findl(L + 1);
		if(R - l + 1 < 3) break;
		if(cmp(L, R, l, R)) {
			L = l;
		} else break;
	}
	while(true) {
		int r = findr(R - 1);
		if(r - L + 1 < 3) break;
		if(cmp(L, R, L, r)) {
			R = r;
		} else break;
	}
	int tl = L, tr = R, lstl = L, lstr = R;
	while(tl - 1 >= 1) {
		if(cmp(lstl, R, tl - 1, R)) {
			lstl = tl - 1;
		}
		tl--;
	}
	while(tr + 1 <= n) {
		if(cmp(L, lstr, L, tr + 1)) {
			lstr = tr + 1;
		}
		tr++;
	}
	L = lstl, R = lstr;
	std::cout << std::fixed << std::setprecision(15) << (long double)(pre[R] - pre[L - 1]) / (R - L + 1) << '\n';
}

int main() {
	std::ios::sync_with_stdio(false);
	std::cin.tie(nullptr);

	int t;
	std::cin >> t;
	while(t--) solve();
	return 0;
}