#pragma GCC optimize(3)
#pragma GCC optimize("Ofast,no-stack-protector")
#include <bits/stdc++.h>

using namespace std ;

using i64 = long long ;
using i128 = __int128;

std::ostream &operator<<(std::ostream &os, i128 n) {
    std::string s;
    while (n) {
        s += '0' + n % 10;
        n /= 10;
    }
    std::reverse(s.begin(), s.end());
    return os << s;
}

const int N = 3e5 + 10 , inf = 0x3f3f3f3f ; 

int a[N] , n ; 

void solve()
{
	cin >> n ;
	int pos = 0 ; 
	i64 s1 = 0 , s2 = 0 , s3 = 0 ;

	for(int i = 1 ; i <= n ; i++) 
	{
		cin >> a[i] ;
		s3 += a[i] ; 
		if ( a[i] > a[i - 1] && !pos ) pos = i ;
	}
	
	for(int i = 1 ; i <= pos + 1 ; i++) s1 += a[i] ;
	for(int i = pos - 1 ; i <= n ; i++) s2 += a[i] ;

	double ret1 = (double) s1 / (pos + 1) , ret2 = (double) s2 / (n - pos + 2) , ret3 = (double) s3 / n ; 

	cout << max({ret1 , ret2 , ret3}) << '\n' ;
}

int main()
{
	ios::sync_with_stdio(false) ; cin.tie(0) ; cout.tie(0) ;
	cout << fixed << setprecision(20) ;
	int t = 1 ;
	cin >> t ;

	a[0] = inf ; 

	for(int i = 1 ; i <= t ; i++)
	{
		// cout << "case #" << i << " : " << '\n' ;
		solve() ; 
	}
	return 0 ; 
}