In: Statistics and Probability
Let X be a random variable that denotes the duration of the song.
It is given that 
The PDF of X is given as:
where 
 in minutes.
(A) So, the required probability is given as:







(B) Now the transformation used when we are standardising is:

where Z is the standard beta variable.
By formula, 
Thus, the mean is given by:

Also, by formula 
Thus, the variance is given by:
