#include <bits/stdc++.h> #define ll long long int #define ld long double using namespace std; void mainSolve() { int n; cin >> n; vector<ld> v(n); for (int i = 0; i < n; i++) cin >> v[i]; sort(v.begin(), v.end()); ld sum = 0.0; ld ans = 0.0; ld cur = 0.0; for (int i = 0; i < n; i++) sum += v[i]; for (int i = 0; i < n; i++) { cur += v[i]; ans = max(ans, (cur / (i + 1) + sum - cur) / (n - i)); } cout << fixed << setprecision(10) << ans << endl; } int main() { #ifndef ONLINE_JUDGE freopen("input.txt", "r", stdin); freopen("output.txt", "w", stdout); #endif int t; cin >> t; while (t--) { mainSolve(); } return 0; }