#include <bits/stdc++.h>

void solve() 
{
    int n;
    std::cin >> n;
    std::vector<int> a(n);
    std::vector<int64_t> pre(n + 1);
    int pos = -1;
    for (int i = 0; i < n; ++i) {
        std::cin >> a[i];
        pre[i + 1] = pre[i] + a[i];
    }
    for (int i = 1; i < n - 1; ++i) {
        if (a[i] > a[i - 1] && a[i] < a[i + 1]) {
            pos = i;
        }
    }
    int l = 0, r = n - 1, len = n;
    for (int i = 0; i < pos - 1; ++i) {
        if ((pre[n] - pre[i + 1]) * (n - l) >= (pre[n] - pre[l]) * (n - i + 1)) {
            l = i + 1;
        } else {
            break;
        }
    }
    for (int i = n - 1; i > pos + 1; --i) {
        if ((pre[i] - pre[0]) * (r + 1) >= (pre[r + 1] - pre[0]) * i) {
            r = i - 1;
        } else {
            break;
        }
    };
    std::cout.setf(std::ios::fixed);
    std::cout << std::setprecision(15) << double(pre[r + 1] - pre[l]) / (r - l + 1) << '\n';
}

int main() 
{
    std::cin.tie(nullptr)->std::ios::sync_with_stdio(false);
    
    int t;
    std::cin >> t;
    while(t--) {
        solve();
    }
    
    return 0;
}