calculating the average/mean

Hi,

Im trying to calculate the mean/average of numbers in an array any suggestions with the mean() would be very much appreciated.:)

how can i get the length of an array to perform in a simple / maths problem whilst being flexiable to the length of the array?:crazy:

function sum()
{
var i=0
for (i=0, total=0;i <numbers.length; i++)
{
total += numbers[i];
}
document.getElementById("txtTotal").value = total;
}



function mean()
{

document.getElementById("answer") = parseFloat(document.getElementById("txtTotal").value) / parseFloat(numbers.length);
}

Try this.

Code JavaScript:

---

 var numberArray=[1,2,3,4,5], thisTotal=0,thisAverage=0;
// add elements of array together 
 for(var i=0;i<numberArray.length;i++)
  {thisTotal+=numberArray[i];}
// calculate average  
 thisAverage=(thisTotal/numberArray.length);
// display result 
 alert(thisAverage)

---

I've whipped up some functions that calculate mean, median, mode, and range.

Code javascript:

---

 
function mean(numbers) {
    // mean of [3, 5, 4, 4, 1, 1, 2, 3] is 2.875
    var total = 0,
        i;
    for (i = 0; i < numbers.length; i += 1) {
        total += numbers[i];
    }
    return total / numbers.length;
}
function median(numbers) {
    // median of [3, 5, 4, 4, 1, 1, 2, 3] = 3
    var median = 0,
        numsLen = numbers.length;
    numbers.sort();
    if (numsLen % 2 === 0) { // is even
        // average of two middle numbers
        median = (numbers[numsLen / 2 - 1] + numbers[numsLen / 2]) / 2;
    } else { // is odd
        // middle number only
        median = numbers[(numsLen - 1) / 2];
    }
    return median;
}
function mode(numbers) {
    // as result can be bimodal or multimodal,
    // the returned result is provided as an array
    // mode of [3, 5, 4, 4, 1, 1, 2, 3] = [1, 3, 4]
    var modes = [],
        count = [],
        i,
        number,
        maxIndex = 0;
    for (i = 0; i < numbers.length; i += 1) {
        number = numbers[i];
        count[number] = (count[number] || 0) + 1;
        if (count[number] > maxIndex) {
            maxIndex = count[number];
        }
    }
    for (i in count) if (count.hasOwnProperty(i)) {
        if (count[i] === maxIndex) {
            modes.push(Number(i));
        }
    }
    return modes;
}
function range(numbers) {
    // range of [3, 5, 4, 4, 1, 1, 2, 3] is [1, 5]
    numbers.sort();
    return [numbers[0], numbers[numbers.length - 1]];
}

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