Learn Advanced Array Methods by Building a Statistics Calculator - Step 51

JavaScript
1

Tell us what’s happening:

The instruction is:
Divide your .reduce() call by the length of the array (in your variance declaration). Then, return variance.
Error:
You should divide the result of the .reduce() call by the length of the array.

Problem: If I run this through the app it runs with no errors and provides the correct value. I am at a loss here. I assume it is something simple that I am missing. Any assistance in this regard would be much appreciated. Thank you.

Your code so far

<!-- file: index.html -->


/* file: styles.css */


/* file: script.js */
// User Editable Region

const getVariance = (array) => {
  const mean = getMean(array);
  const variance = array.reduce((acc, el) => {
  const difference = el - mean;
  const squared = difference ** 2;
    return acc + squared / array.length;
}, 0);
    return variance
}


// User Editable Region

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/125.0.0.0 Safari/537.36

Challenge Information:

Learn Advanced Array Methods by Building a Statistics Calculator - Step 51

2

you need to make the new operation outside the reduce method, not inside its callback. Even if the result is correct, it is not what you are asked to do.

3

Hi Ilenia, thank you. Still not getting it. Don’t worry, I’ll keep trying to figure it out. You’re a star.

4

Hi Ilenia, got it thank you. It was staring me in the face the whole time, I just didn’t see it. I think I got into an analysis paralysis tailspin for a while there. Thanks a million, you got the plane righted just before it hit the ground.

5

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