#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;
const __int128_t st = 1;
void solve()
{
    int n, s;
    cin >> n;
    vector<ll> a(n + 1);
    for (int i = 1; i <= n; i++)
        cin >> a[i];
    for (int i = 1; i <= n; i++)
        if (i > 1 && i < n && a[i - 1] > a[i] && a[i + 1] > a[i])
            s = i;
    ll pre = 0, suf = 0;
    pll ans = {0, 0};
    // cout << s << endl;
    for (int i = 1; i <= n; i++)
    {
        if (i <= s)
            pre += a[i];
        if (i >= s)
            suf += a[i];
    }
    ll res = 0, cnt = 0;

    auto cmp = [](pll a, pll b) -> bool
    {
        if (a.first + a.second == 0)
            return 1;
        return st * b.first * a.second > st * b.second * a.first;
    };
    for (int i = s - 1; i >= 1; i--)
    {
        res += a[i], cnt++;
        if (cmp(ans, pll(suf + res, n - i + 1)))
            ans = pll(suf + res, n - i + 1);
    }
    res = 0, cnt = 0;
    for (int i = s + 1; i <= n; i++)
    {
        res += a[i], cnt++;
        if (cmp(ans, pll(pre + res, i)))
            ans = pll(pre + res, i);
    }
    long double up = ans.first;
    long double down = ans.second;
    // cout << up << " " << down << endl;
    cout << up / down << endl;
}
int main()
{
#ifdef x3ea
    freopen("in.txt", "r", stdin);
    freopen("out.txt", "w", stdout);
#endif
    cout << fixed << setprecision(11);
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    int _ = 1;
    cin >> _;
    for (; _; _--)
        solve();
}