Producing data is a first step in four-steps process data.
In this step, we choose a individuals that included in the sample from population. We collect data from individuals to move EDA.

In this step have 2 stage:

  • Sampling
  • Study design


In previous section, we said to sampling is a…

You can use let or var keyword to declare variable, object in JavaScript. But, what’s different between them?

Keyword let allow you declare variables that are limited to a scope of a block statement ({}).
Look a below example:

function func() {
let t = ‘hello world’ ; // t is exists in this scope
t = ‘javascript’ // Error

Keyword var declare global variables in script. They are processed before any code is executed. This lead to problem which is call Hoisting (You can search more to understand 😁)
Here a example:

k = ‘first’ // Hoisting
function func() {
var k = ‘second’ // Declare here
k = ‘third’ // Valid assign

We usually use let to declare variable, object, and var to declare function. This help your code is safely, less bug.

JavaScript is a popular language programming to develop web application today. It is simple and powerful. We can easily use JavaScript on most browers (Chrome, FireFox, …). I have some recommend help you to learning and improve JavaScript skill better. 😊



It covers almost topics in Web Development. You learn…

du nguyen


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