Basic Statistics Part I

  • How to obtain and sample data
  • The measures of center, variance, and relative standing
  • Normalization of data using the z-score
  • The Empirical rule

What are statistics?

This might seem like an odd question to ask, but I am frequently surprised by the number of people who cannot answer this simple and yet powerful question: what are statistics? Statistics are the numbers you always see on the news and in the paper. Statistics are useful when trying to prove a point or trying to scare you, but what are they?

How do we obtain and sample data?

If statistics is about taking samples of populations, it must be very important to know how we obtain these samples, and you’d be correct. Let’s focus on just a few of the many ways of obtaining and sampling data.

Obtaining data

There are two main ways of collecting data for our analysis: observational and
experimentation. Both these ways have their pros and cons, of course. They each produce different types of behavior and, therefore, warrant different types of analysis.


We might obtain data through observational means, which consists of measuring specific characteristics but not attempting to modify the subjects being studied. For example, you have tracking software on your website that observes users’ behavior on the website, such as length of time spent on certain pages and the rate of clicking on ads, all the while not affecting the user’s experience, then that would be an observational study.



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Desi Ratna Ningsih

Desi Ratna Ningsih

Data Science Enthusiast, Remote Worker, Course Trainer, Archery Coach, Psychology and Philosophy Student