# My Umbrella

Written by Rasheedat Raji · 2 min read

These days a lot of people walk around with an object that looks like a walking stick. This is usually more often during the rainy season in this part of the world. I am sure a lot of you would have guessed correctly- an umbrella. Why is this so? Why is it more prominent during the rainy season as against the dry season? Could it be the norm in society, fashion, or just based on our intuition? Some do not own an umbrella at all. You may ask, why all these questions? Why is it relevant?

Our minds/intuition carry out some experiments consciously or subconsciously, hence the reason we behave the way we do. Permit me to educate us a little bit about probability.

Probability refers to the numeric measure of the likelihood/chances/odds that an event would occur. We live in a world of uncertainty, hence the importance of this terminology. We assign a probability of one to an event that is almost certain to occur while zero to one that is never likely to occur. For example, in a school system, it is highly likely you would write an exam at the end of the session while it is highly unlikely to have snowfall in Nigeria due to our climate.

Now, I mentioned an event, what does this term mean. An event is a thing that happens. In statistics, an experimental event is any process that generates well-defined outcomes for example when you toss a coin, you have just two outcomes, either a head or a tail. They both have equal chances of occurring. This method of assigning probability is called classical probability (50/50 chance).

Another method of assigning probability is the relative frequency method. This is the process of assigning probability based on past experimental results such as saying there is a probability of selling fifty pairs of shoes in January 2021 because I sold fifty pairs in January 2020.

The last method is subjective probability, which is based on our intuition. We assign probability based on what our minds tell us. Adding to the example above, I might decide to say it is highly likely I sell seventy pairs because I believe the economy would be better hence more people can afford it.

If you notice, I highlighted the word “because”, this shows that sometimes, determining the probability of an event occurring is dependent on another event. The two events are therefore dependent.

Back to my umbrella story, the probability of rainfall during the rainy season is higher than the probability of rainfall during the dry season which is why a lot of people move around with it to protect themselves from getting wet. You can imagine having an interview and you forget to go out with an umbrella and it rains heavily on that day, I do not want to imagine. Now, those that move without an umbrella might have used their intuition to determine that it is not likely to rain on a particular day. Although we have weather forecasts, listening to the weather forecast is not very common among certain groups of people in this part of the world.

Lastly, let me talk a little about conditional probability, this is the probability of an event occurring subject to a prior event having occurred. A good example of this is an electric fan, the functionality of this fan is dependent on the availability of electricity. Hence functionality of an electric fan is dependent on the availability of electricity (prior event).

We have several formulas for calculating these probabilities, but I am not going to bore you with those statistics today.

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