As we know in the case of quantum mechanics to know the basic details of a quantum particle, we need
to know the state say, and with the help of say, we can then know the rest of the details of a quantum
state.
Now, let's say I have an ensemble quantum state prepared with the help of test tubes.
Let's see, each of these test tubes are identical.
And there is a quantum particle located at specific position in these test tubes as this is a quantum
particle and being probabilistic in nature, its position is not fixed and this would vary across test
tubes.
So we will find the probability density to discover this particle in this ensemble of quantum state
and make the formula simpler to understand and apply for our needs.
This process is called this normalization of whale function.