#include<bits/stdc++.h>
#define ll long long
#define alls(x) x.begin(),x.end()
#define ull unsigned long long
#define lowbit(x) x&-x
#define lc p<<1
#define rc p<<1|1
#define PII pair<int,int>
#define vi vector<int>
using namespace std;
const int mod = 998244353;
const int N = 2e5+10;
void solve()
{
    int n;
    cin >> n;
    vi a(n);
    for(auto &i:a)cin >> i;
    double sum = 0;
    for(auto i:a)sum+=i;
    sum/=n;
    int x = 0;
    for(int i = 0;i<n;i++)
    {
        if(a[i]>a[i-1] && a[i]<a[i+1]) {
            x = i;
            break;
        }
    }
    double ans = sum;
    sum = 0;
    for(int i = 0;i<=x+1;i++)sum+=a[i];
    ans = max(ans,sum/(x+2));
    sum = 0;
    for(int i = x-1;i<n;i++)sum+=a[i];
    ans = max(ans,sum/(n-x+1));
    cout<<ans<<'\n';
}
signed main()
{
    cout<<fixed<<setprecision(20);
    ios::sync_with_stdio(false),cin.tie(nullptr),cout.tie(nullptr);
    int _ = 1;
    cin >> _;
    while(_--)solve();
}