Question

It is often said that we are all different and that what is right for one person is not necessarily right for another. This can be interpreted statistically as variability.

Why does variability exist?

Is it good or is it bad, please provide examples?

How important do you think it is to measure and describe in the field of statistics?

Answer 1

Why does variability exist?

There are many reasons of the presence of variability in the different situations.

Let's take some examples:

Suppose, the arrival time of a particular train on a particular station is 2:00 pm.

If we take the last 30 day's arrival time data of this train then we can observed that there is variability in the arrival times of the train. This is because the situation are not identical of every days. Sometimes because of good weather the train came before 2:00 pm, and sometimes it is came after 2:00 pm, due to the bad weather or some technical issues. Also the change of the drivers may affect the arrival time of the trains.

Another example: Suppose we want to measure the height of the students in a particular class. We know that the height of all the students are different. This is because the genetical, or the awareness of parents, and many other reasons.

So there are many example such as production of the items in the industries, different kinds of services and so on, where we observed variations.

Note: Most of the time variability is unavoidable because the situations are not at all identical, or it is very difficult to fix all the conditions are identical.

Is it good or is it bad, please provide examples?

Some times it is good and some times it is bad.

Suppose we want to make the wheel of the trains. So we must want to keep the variability of the wheel as low as possible, otherwise there is a chance of accidents.

Variability in a IQ , personnel talents of the people are very large. In this case variability is good because, on the basis of these qualities, the life of the peoples is look as more interesting.

How important do you think it is to measure and describe in the field of statistics?

It is important because on the basis of the central tendencies we can not find the characteristics of the statistical populations. If we know the variability of the population then we can take better decision about the population.