curriculum/challenges/english/blocks/learn-advanced-array-methods-by-building-a-statistics-calculator/661899113600ef307d8a7487.md
To get the median of an array with an odd number of elements, you will need to find and return the middle number.
Here is how to find the middle number of an array with an odd number of elements:
arr[Math.floor(arr.length / 2)];
Here is a longer example finding the middle number of an array with 5 elements:
const numbers = [1, 2, 3, 4, 5];
const middleNumber = numbers[Math.floor(numbers.length / 2)];
console.log(middleNumber); // 3
The reason why you use Math.floor is because the result of dividing an odd number by 2 will be a decimal. Math.floor will round down to the nearest whole number.
Declare an oddListMedian variable and assign it the result of finding the middle number of the testArr1. Then log the oddListMedian variable to the console.
Open up the console to see the result.
You should have an oddListMedian variable.
assert.isDefined(oddListMedian);
You should assign the result of finding the middle number for the testArr1 to the oddListMedian variable. Remember to refer to the example from earlier: arr[Math.floor(arr.length / 2)];
assert.strictEqual(oddListMedian, 3);
You should have a console statement that logs the oddListMedian variable.
assert.match(code, /console\.log\(\s*oddListMedian\s*\);?/);
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1" />
<link rel="stylesheet" href="./styles.css" />
<script src="./script.js"></script>
<title>Statistics Calculator</title>
</head>
<body>
<h1>Statistics Calculator</h1>
<p>Enter a list of comma-separated numbers.</p>
<form onsubmit="calculate(); return false;">
<label for="numbers">Numbers:</label>
<input type="text" name="numbers" id="numbers" />
<button type="submit">Calculate</button>
</form>
<div class="results">
<p>
The <dfn>mean</dfn> of a list of numbers is the average, calculated by
taking the sum of all numbers and dividing that by the count of numbers.
</p>
<p class="bold">Mean: <span id="mean"></span></p>
<p>
The <dfn>median</dfn> of a list of numbers is the number that appears in
the middle of the list, when sorted from least to greatest.
</p>
<p class="bold">Median: <span id="median"></span></p>
<p>
The <dfn>mode</dfn> of a list of numbers is the number that appears most
often in the list.
</p>
<p class="bold">Mode: <span id="mode"></span></p>
<p>
The <dfn>range</dfn> of a list of numbers is the difference between the
largest and smallest numbers in the list.
</p>
<p class="bold">Range: <span id="range"></span></p>
<p>
The <dfn>variance</dfn> of a list of numbers measures how far the values
are from the mean, on average.
</p>
<p class="bold">Variance: <span id="variance"></span></p>
<p>
The <dfn>standard deviation</dfn> of a list of numbers is the square
root of the variance.
</p>
<p class="bold">
Standard Deviation: <span id="standardDeviation"></span>
</p>
</div>
</body>
</html>
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;
}
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];
const isEven = testArr2.length % 2 === 0;
console.log(isEven);
--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;
}