#include <stdio.h>
#include <stdlib.h>
#include <memory.h>

#define MAX_SIZE 1002
#define MAXNUM 9999
int arrData[MAX_SIZE];

double result;
void Init();
void InputData();
double _recuData(int teamNum,int arrNum, double minNum);

int main()
{
    int i = 0 ;
    int testCase = 0 ;
    scanf("%d",&testCase);
    for( i = 0 ; i<testCase; i++)
    {
        Init();
        InputData();
    }
    return 0 ;
}

void Init()
{
    memset(arrData,0,sizeof(arrData)/sizeof(int));

}

void InputData()
{
    int i  = 0 ;
    int arrNum  = 0 ;
    int teamNum = 0 ;
    scanf("%d %d",&arrNum,&teamNum);
    for(i = 0 ; i<arrNum; i++)
    {
        scanf("%d",&arrData[i]);
    }
    _recuData(teamNum,arrNum,MAXNUM);

}
double _recuData(int teamNum,int arrNum,double minNum)
{
    int i = 0 ;
    double min = 0 ;
    int startIndex = 0 ;
    if(teamNum == arrNum)
    {
        for( i = 0 ; i<teamNum ; i ++)
        {
            min = min + arrData[startIndex+i];
        }
        if(min/teamNum <minNum)
        {
            minNum = min/teamNum ;
        }
        printf("%.12f\n",minNum);
        return minNum;
    }
    for( startIndex = 0 ; startIndex < arrNum ;  startIndex++)
    {
        for( i = 0 ; i<teamNum ; i ++)
        {
            min = min + arrData[startIndex+i];
        }
        if(min/teamNum <minNum)
        {
            minNum = min/teamNum ;
        }
    }
    teamNum++;
    _recuData(teamNum,arrNum,minNum);

}