function showOverNumbers(data) {

    var sum = []
    var items = 0;

    var arr = [...data]
    while(arr[0]) {
        items++
        arr.splice(0, 1)
    }

    sum[0] = 0
    for(var i = 0; i < items; i++) {
        sum[0] += data[i]
    }


    const avg = sum / items

    var result = []
    var counter = items
    while(counter) {
        if(data[items - counter] > avg)
            result[items - counter] = data[items - counter]

        counter--;
    }

    return result.filter(function(r) {
        return r != 0
    })
}

const data = [4,2,3,5,10,5,6,7,8,9]
const result = showOverNumbers(data)

console.log(result)