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

void solve() {
    int n;
    scanf("%d", &n);

    vector<long long> a(n + 2, 0);
    a[0] = LLONG_MAX;
    a[n + 1] = LLONG_MAX;

    for (ll i = 1; i <= n; i++) {
        scanf("%lld", &a[i]);
    }

    ll tip = -1;
    for (ll i = 2; i <= n - 1; i++) {
        if (a[i - 1] > a[i] && a[i] < a[i + 1]) {
            tip = i;
            break;
        }
    }
    if (tip == -1) tip = 1;

    vector<long long> pre(n + 2, 0);
    for (ll i = 1; i <= n; i++) {
        pre[i] = pre[i - 1] + a[i];
    }

    ld maxAvg = 0.0;
    ld avgAll = (ld)pre[n] / n;
    if (avgAll > maxAvg) {
        maxAvg = avgAll;
    }

    ll st = 0;

    for (ll l = 1; l <= tip - 2; l++) {
        if (a[l] > a[l + 1]) {
            ll len = n - l + 1;
            long long sum = pre[n] - pre[l - 1];
            ld avg = (ld)sum / len;
            if (avg > maxAvg) {
                maxAvg = avg;
                st = l - 1;
            }
        } else {
            break;
        }
    }

    for (ll r = n; r >= tip + 2; r--) {
        if (a[r] > a[r - 1]) {
            ll len = r - st;
            long long sum = pre[r] - pre[st];
            ld avg = (ld)sum / len;
            if (avg > maxAvg) {
                maxAvg = avg;
            }
        } else {
            break;
        }
    }

    if (n >= 3) {
        long long sum = a[tip - 1] + a[tip] + a[tip + 1];
        ld avg = sum / 3.0;
        if (avg > maxAvg) {
            maxAvg = avg;
        }
    }

    printf("%.20Lf\n", maxAvg);
}

int main() {
    int t;
    scanf("%d", &t);
    while (t--) solve();
    return 0;
}