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

void solve() {
    int n;
    cin >> n;
    vector<int> a(n);
    for (auto &e: a) cin >> e;

    int m = 0;
    for (int i = 1; i < n; i++) {
        if (a[i-1] < a[i]) break;
        m++;
    }
    assert(m != 0 && m != n-1);

    vector<long long> ps(n+1, 0);
    for (int i = 0; i < n; i++) {
        ps[i+1] = ps[i] + a[i];
    }

    double ans = 0;
    for (int i = 0; i < m; i++) {
        ans = max(ans, (double)(ps[n] - ps[i]) / (n - i));
    }
    for (int i = m+1; i < n; i++) {
        ans = max(ans, (double)(ps[i+1]) / (i+1));
    }

    cout << fixed << setprecision(12) << ans << '\n';
}

int main() {
    cin.tie(0)->sync_with_stdio(0);

    int t;
    cin >> t;
    for (; t; t--) solve();

    return 0;
}