The normal distribution curve can be used to assign probabilities to values. Every data point can be condensed into two numbers, the mean of the curve which measures the average, and the variance, which measures the dispersion of the curve.

The normal distribution curve is symmetric about their mean and finds application in many areas of nature. The average height of the test scores, size of flora and fauna, life spans can all be modelled by the normal distribution curve. A very important theorem is the central limit theorem, where adding or averaging the random variables produces a normal distribution curve.

Are there different kinds of distributions ?

When random variables are added together, the resulting distribution curve is likely to be normal. But when random variables are multiplied together, a different distribution curve results. This is a lognormal distribution.

Salary raises are typically expressed as a percentage increment. So folks with higher salaries