#include <iostream>
#include <cstring>
#include <algorithm>
#include <map>
#include <vector>
#include <set>
#include <queue>
#include <cmath>
#include <stack>
#include <cstring>
#include <iomanip>
#include <unordered_map>
#include <numeric>

#define sc_int(x) scanf("%d", &x)

#define x first
#define y second
#define pb push_back

using namespace std;

const int N = 510, M = 2e5 + 10, MOD = 1e9 + 7;
const int inf = 1e9;

typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int, int> PII;
typedef pair<string, int> PSI;
typedef pair<LL, LL> PLL;
typedef pair<double, double> PDD;
typedef pair<char, int> PCI;
typedef pair<string, string> PSS;

int n, m;

void solve() 
{
    cin >> n;
    vector<LL> a(n + 1);
    LL sum = 0;
    for(int i = 1; i <= n; i ++) cin >> a[i], sum += a[i];
    int pos = 0;
    for(int i = 1; i <= n; i ++)
    {
        if(a[i] < a[i + 1])
        {
            pos = i;
            break;
        }
    }
    LL num = n;
    int l = 1;
    int r = n;
    while(1)
    {
        bool flag = false;
        while(l + 1 < pos && sum > a[l] * num) sum -= a[l], l ++, num --, flag = true;
        while(r - 1 < pos && sum > a[r] * num) sum -= a[r], r --, num --, flag = true;
        if(!flag) break;
    }
    printf("%.15lf\n", 1.0 * sum / num);
}

int main()
{
    // freopen("input.txt","r",stdin);
    // freopen("output.txt","w",stdout);
    // ios::sync_with_stdio(false),cin.tie(0),cout.tie(0);
    
    int T = 1;
    cin >> T;
    while(T --)
    {
        solve();
    }
}