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  • Let's start from the types of data we can have.

  • There is categorical and numerical data.

  • Categorical data describes categories or groups.

  • One example is car brands like Mercedes, BMW and Audithey show different categories.

  • Another instance is answers to yes and no questions.

  • If I ask questions like: Are you currently enrolled in a university?

  • Or, Do you own a car?

  • Yes and no would be the two groups of answers that can be obtained.

  • This is categorical data.

  • *** Numerical data, on the other hand, as its

  • name suggests, represents numbers.

  • It is further divided into two subsets: discrete and continuous.

  • Discrete data can usually be counted in a finite matter.

  • A good example would be the number of children that you want to have.

  • Even if you don't know exactly how many, you are absolutely sure that the value will

  • be an integer such as 0, 1, 2, or even 10.

  • Another instance is grades on the SAT exam.

  • You may get 1000, 1560, 1570 or 2400.

  • What is important for a variable to be defined as discrete is that you can imagine each member

  • of the dataset.

  • Knowing that SAT scores range from 600 to 2400 and 10 points separate all possible scores

  • that can be obtained is key.

  • It's easier to understand discrete data by saying it's the opposite of continuous

  • data.

  • Continuous data is infinite and impossible to count.

  • For instance, your weight can take on every value in some range.

  • Let's dig a bit deeper into this.

  • You get on the scale and the screen shows 150 pounds, or 68.0389 kilograms.

  • But this is just an approximation.

  • If you gain 0.01 pound, the figure on the scale is unlikely to change, but your new

  • weight will be 150.01 pounds or 68.0434 kilograms.

  • Now think about sweating.

  • Every drop of sweat reduces your weight by the weight of that drop, but once again, a

  • scale is unlikely to capture that change.

  • The process of losing and gaining weight occurs all the time.

  • Your exact weight is a continuous variableit can take on an infinite amount of values

  • no matter how many digits there are after the dot.

  • To sum up, your weight can vary by incomprehensibly small amounts and is continuous, while the

  • number of children you want have is directly understandable and is discrete.

  • Just to make surehere are some other examples of discrete and continuous data:

  • Grades at university are discrete – A, B, C, D, E, F, or 0 to 100 percent.

  • The number of objects in general.

  • No matter if bottles, glasses, tables, or cars.

  • They can only take integer valuesMoney can be considered both, but physical

  • money like banknotes and coins are definitely discrete.

  • You can't pay $1.243.

  • You can only pay $1.24.

  • That's because the difference between two sums of money can be 1 cent at most.

  • What else is continuous?

  • Apart from weight, other measurements are also continuous.

  • Examples are: • Height

  • AreaDistance

  • And time All of these can vary by infinitely smaller

  • amounts, incomprehensible for a human.

  • Time on a clock is discrete, but time in general isn't!

  • It can be anything like 72.123456 seconds.

  • We are constrained in measuring weight, height, area, distance, and time by our technology,

  • but in general, they can take on any value.

  • Alright!

  • These were the types of data.

Let's start from the types of data we can have.

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