#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 3e5 + 5;

int a[N];
int n;

void solve()
{
    cin >> n;

    a[0] = 0x3f3f3f3f;
    int p = 0;
    for (int i = 1; i <= n; i++)
    {
        cin >> a[i];
        if (a[i] > a[i - 1])
            p = i - 1;
    }

    ll sum = 0;
    double ans = 0;

    sum = 0;
    for (int i = 1; i <= n; i++)
    {
        sum += a[i];
        if (i > p)
            ans = max(ans, 1.0 * sum / i);
    }

    sum = 0;
    for (int i = n; i >= 1; i--)
    {
        sum += a[i];
        if (i < p)
            ans = max(ans, 1.0 * sum / (n - i + 1));
    }

    cout << fixed << setprecision(15) << ans << endl;
}

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

    int t = 1;
    cin >> t;
    while (t--)
        solve();

    return 0;
}