Question

Explain why 1.21 cannot be the probability of some event.

	a.	A probability must be negative.
	b.	A probability proportion must be between zero and one.
	c.	A probability must be an integer.

Answer 1

We know that probability of an event can be only be found between 0 and 1(inclusive)

This is because the probability is defined as ratio of favorable outcome to the total outcome

so, largest possible value for favorable outcome will be equal to the total outcome, but it cant be more than total outcome. In this case, we get maximum possible probability, i.e. p = favorable outcome/total outcome = 1/1 = 1

and minimum possible value for favorable outcome can only be 0, which will give us minimum possible probability p = 0/total outcome = 0

therefore, only option B is correct

option A is incorrect because probability can never be negative as we know that favorable outcome for an event can never be negative

option C is incorrect because probability can only be integer when it is 1, but this is maximum possible probability. So, most of the time probability is given in decimal format