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

#define PB push_back
#define endl '\n'

typedef long long ll;
typedef vector<int> vi;
typedef pair<int, int> pii;
typedef vector<pii> vpii;
typedef vector<ll> vll;
typedef long double ld;

void solve(int tt) {
    int n;
    cin >> n;
    vll a(n+1);
    vll c(n+1);
    for (int i = 1; i <= n; ++i) {
        cin >> a[i];
        c[i] = c[i-1] + a[i];
    }
    ld ans = c[n] / (ld)n;
    for (int i = 2; i < n; ++i) {
        if (a[i] < a[i+1]) {
            ans = max(ans, c[i+1] / (ld)(i+1));
            ans = max(ans, (c[n] - c[i-2]) / (ld)(n - (i-2)));
        }
    }
    cout << fixed << setprecision(12) << ans << endl;
}

int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
    int tc = 1;
    cin >> tc;
    for (int i = 1; i <= tc; ++i) {
        solve(i);
    }
    return 0;
}