--- id: 661890c4abae9f2a0eddad6b title: Step 22 challengeType: 0 dashedName: step-22 --- # --description-- In the next few steps, you'll learn how to determine if an array's length is even or odd, as well as how to find the median. You will then be able to apply what you learned to the `getMedian` function. To check if a number is even or odd, you can use the modulus operator `%`. The modulus operator returns the remainder of the division of two numbers. Here is an example checking if an array length is even or odd: ```js // check if array length is even arr.length % 2 === 0; // check if array length is odd arr.length % 2 === 1; ``` If the remainder is `0`, the number is even. If the remainder is `1`, the number is odd. Create a variable called `isEven`. Then use the modulus operator to check if the length of the `testArr2` array is even. Assign that expression to the `isEven` variable. Below your `isEven` variable, log out the `isEven` variable to the console. Open up the console to see the result. # --hints-- You should have an `isEven` variable. ```js assert.isDefined(isEven); ``` You should check if the length of the `testArr2` array is even. Refer back to the example provided for you: `arr.length % 2 === 0;` ```js assert.isTrue(isEven); ``` You should have a `console.log` statement that logs the `isEven` variable. ```js assert.match(code, /console\.log\(isEven\)/); ``` # --seed-- ## --seed-contents-- ```html Statistics Calculator

Statistics Calculator

Enter a list of comma-separated numbers.

The mean of a list of numbers is the average, calculated by taking the sum of all numbers and dividing that by the count of numbers.

Mean:

The median of a list of numbers is the number that appears in the middle of the list, when sorted from least to greatest.

Median:

The mode of a list of numbers is the number that appears most often in the list.

Mode:

The range of a list of numbers is the difference between the largest and smallest numbers in the list.

Range:

The variance of a list of numbers measures how far the values are from the mean, on average.

Variance:

The standard deviation of a list of numbers is the square root of the variance.

Standard Deviation:

``` ```css body { margin: 0; background-color: rgb(27, 27, 50); text-align: center; color: #fff; } button { cursor: pointer; background-color: rgb(59, 59, 79); border: 3px solid white; color: white; } input { background-color: rgb(10, 10, 35); color: white; border: 1px solid rgb(59, 59, 79); } .bold { font-weight: bold; } ``` ```js const getMean = (array) => array.reduce((acc, el) => acc + el, 0) / array.length; --fcc-editable-region-- const testArr1 = [1, 2, 3, 4, 5]; const testArr2 = [1, 2, 3, 4, 5, 6]; --fcc-editable-region-- const getMedian = (array) => { const sorted = array.sort((a, b) => a - b); } const calculate = () => { const value = document.querySelector("#numbers").value; const array = value.split(/,\s*/g); const numbers = array.map(el => Number(el)).filter(el => !isNaN(el)); const mean = getMean(numbers); document.querySelector("#mean").textContent = mean; } ```