import java.text.DecimalFormat;
import java.util.Scanner;


public class Main {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int testCases =  sc.nextInt();


        while(testCases-- > 0) {
            //날짜와 팀을 받는
            sc = new Scanner(System.in);

            int day = sc.nextInt();
            int team = sc.nextInt();     


            int[] dayCost = new  int[day];

            sc = new Scanner(System.in);
            for (int ii = 0; ii < day; ii++) {

                dayCost[ii] = sc.nextInt(); 

            }



            DecimalFormat df = new DecimalFormat("0.00000000000");          
            System.out.println(df.format(minCoset(team, dayCost, 0, 0)));   
        }

    }

    private static double minCoset(int team, int[] dayCost ,int startIndex , double avg ){
        int sum = 0 ;       
        if((dayCost.length < startIndex + team) && (team  > dayCost.length)  )          
            return avg;

        if(dayCost.length < startIndex + team){
            team ++;            
            return minCoset(team,  dayCost ,0 , avg );
        }       
        for (int i = startIndex; i < ( startIndex + team); i++) {
            sum += dayCost[i];      
        }       
        startIndex++;               
        if(avg ==0 || (double)avg  > (double)sum/(double)team)
            return  minCoset(team,  dayCost ,startIndex , (double)sum/(double)team );
        else
            return  minCoset(team,  dayCost ,startIndex , (double)avg );
    }
}