Question

A spinner is divided into two equal parts, one red and one blue. The set of possible outcomes when the spinner is spun twice is S = {RR, RB, BR, BB}. Let X represent the number of times blue occurs. Which of the following is the probability distribution, PX(x)?

Answer 1

Explanation:

Given that a spinner is divided into two equal parts, one red and one blue.

When the spinner is spun twice, X, the number of times blue occurs can take values as 0,1,2

I.e. either no blue occurs or 1 blue occurs or 2 blue occurs.

P(X=0) = P(RR) = 0.25

P(X=1) = P(RB, BR) = 0.5

P(X=2) = P(BB) =0.25

other wise prob =0

The above is the probability distribution of number of blues

Answer 2

The spinner has 4 possible outcomes: RR, RB, BR, BB. The probability of RR occurring is 1/4, RB, also 1/4, BR, 1/4, BB 1/4. When the probabilities and the outcomes are plotted in a graph, this will display a straight line, thus, called a uniform distribution.