# Deviation from the mean

Written by Happy Rugbere · 2 min read

I still remember my interview session to get into Lagos Business School. I think it was Dr. Bongo and one other faculty who I do not seem to remember anymore. The first thing that went through my mind was, wow, they are so young. I initially felt they were both teaching assistants or other students recruited by the university to interview us. Two weeks later, the same student lecturer stood in front of the class as our Data Analytics (DA) course facilitator. After this introduction, it made sense why I was asked many statistics questions during the interview. I remember struggling to understand the mean, median, and mode concepts right before the interview. You see, statistics had never been my field of strength. Unlike accounting which I knew were used by bankers, I felt the calculations in statistics were vague and did not have any practical use in the real world. Oh boy, was I wrong.

It didn’t take me three classes in DA to understand the numerous applications of statistical concepts in the real world. I learned about its utilization in creating precise prediction models of a population using attributes of a sample set of data and how it can be used in artificial intelligence that mimics real life. I did not only learn how to properly use the mean, median, and mode to extrapolate potential outcomes but also how to notice outliers in a data set. For most of you following my blog, you would say he can’t possibly learn all these in just three months of an MBA program. Well, I water down the things I say here so it does not come off as me marketing for the school. I do not know about other MBA programs, but what I am experiencing here has stretched my mind to its elastic limits, and I heard we are just starting.

Anyway, let us get back to the topic of this piece. As most of us know, the mean of a data set is also known as its average. You can find the mean by adding up the individual values of the events in a data set (X1 + X2 + X3…+Xn) and dividing the sum by the number of data points (n). The concept of average was introduced to us in primary school and was the easiest way to score points on a maths test. We did not know then that this mean value needed to be adjusted for errors because although the mean represents the most likely value of the data set, other data will fall above and below the mean values. The above is the almighty concept of the deviation from the mean. I know the idea sounds simple considering that if you have a set of 5 data points, you could easily subtract each value from the mean value to know how much each deviated above or below the mean value. Have you ever considered having a sample data set of 50,000 samples? What happens then? Or a population size of 200 Million people as we see in most countries?

I am paying 8.5m to learn these things, so I will not tell you further as this will breach the stingy with knowledge agreement I had with my financial health.

Thank you once more for listening to one of my #EMBA27 tales. Until next time, I will leave you with one of my numerous nuggets of wisdom. I will not tell you the author this time; let that be my minor assignment for you to solve on your own.

‘The impediment to action advances action, what stands in the way, becomes the way.’ – By ………..

The first person to guess the author of this statement will get a gift from me.

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