Thread: Discrete random variable – distribution of X

A spinner is made from the disc is the diagram and the random variable X represents the number it lands on after being spun.





Write down the distribution of X.


How could I do this? Basically I’m confused where to start & what to think. Could anyone explain please?

This problem represents a simple idea.
Just find out what percent of the total area each of the sectors represents.
For example, sector 2 is one fourth of the total area.

Originally Posted by Plato

This problem represents a simple idea.
Just find out what percent of the total area each of the sectors represents.
For example, sector 2 is one fourth of the total area.

So remaining area is 1-1/4 = 3/4.
So sector 1 is 3/4 divided by 2 = 3/8.

Is it like that?

Originally Posted by geton

So remaining area is 1-1/4 = 3/4.
So sector 1 is 3/4 divided by 2 = 3/8.

No! Look at the size of the central angles.
Sector 1 is of the total. Sector 3 is of the total.

Well my book's answer says for sector 1, 3/8 and sector 3, 3/8. How this 3/8 come?

Originally Posted by geton

Well my book's answer says for sector 1, 3/8 and sector 3, 3/8. How this 3/8 come?

Well inorder for those answers to be correct the second number in the diagram would have to be not .
So the diagram in incorrect.

Originally Posted by Plato

Well inorder for those answers to be correct the second number in the diagram would have to be not .
So the diagram in incorrect.

It's not my fault. I think it's a printing mistake of my book. Anyways, thank you so much.