The probability distribution for the random variable X is evaluated to be:
- X= 0, P(X = 0) = 0.16
- X = 1, P(X = 1) = 0.48
- X = 2, P(X = 2) = 0.36
What is probability distribution?
Probability distribution of a random variable is the collection of value and its probability pair for values of that considered random variable.
It might be a function, a table etc.
How to calculate the probability of an event?
Suppose that there are finite elementary events in the sample space of the considered experiment, and all are equally likely.
Then, suppose we want to find the probability of an event E.
Then, its probability is given as
[tex]P(E) = \dfrac{\text{Number of favorable cases}}{\text{Number of total cases}} = \dfrac{n(E)}{n(S)}[/tex]
where favorable cases are those elementary events who belong to E, and total cases are the size of the sample space.
For this case, we have:
Spinner has values 1, 2, 3, 4, and 5
Spinner spun twice
- X = number of times an odd number comes.
- A = an odd number comes in first trial
- B = an odd number comes in second trial
A and B are independent events, so their simultaneous occurrence' probability is: [tex]P(A \cap B) = P(A)P(B)[/tex] (from definition independent events and chain rule).
Total odds' counts = 3 (they are 1, 3 and 5) = n(A) = n(B) (number of favorable events)
Total labels on spinner = 5 = n(S)
Thus, P(A) = n(A)/n(S) = P(B) = 3/5
X can be either 0 (no odd number in either of the spins), 1 (single times odd number as outcome), or 2 (both times odd comes).
Calculating the probabilities:
Complement of A and complement of B needs to occur simultaneously.
[tex]P(X = 0) = P(A' \cap B') = P(\overline{A \cup B}) = 1 - P(A \cup B)[/tex]
By addition rule of probability, we get:
[tex]P(A \cup B) = P(A) + P(B) - P(A \cap B)\\\\P(A \cup B) = \dfrac{3}{5} + \dfrac{3}{5} - (\dfrac{3}{5})^2 = \dfrac{21}{25}[/tex]
Thus, [tex]P(X = 0) = 1 - P(A \cup B) = 1 - \dfrac{21}{25} = \dfrac{4}{25} = 0.16[/tex]
Either A or B have to occur. That means it is sum of probability of (A and B' (complement of B))'s occurrence, and probability of (A' and B)'s occurrence
Thus, we get:
[tex]P(X = 1) = P(A \cap B') = P(A)P(B') +P(A' \cap B)\\P(X = 1)= P(A)(1-P(B)) + (1-P(A))P(B) \\P(X = 1)= \dfrac{3}{5}(1-\dfrac{3}{5}) + (1-\dfrac{3}{5})\dfrac{3}{5}\\\\P(X =1) = \dfrac{12}{25}[/tex]
Both A and B has to occur simultaneously in this case. Thus,
[tex]P(X = 2) = P(A \cap B) = P(A)P(B) = (\dfrac{3}{5})^2 = \dfrac{9}{25} = 0.36[/tex]
Thus, the probability distribution for the random variable X is evaluated to be:
- X= 0, P(X = 0) = 0.16
- X = 1, P(X = 1) = 0.48
- X = 2, P(X = 2) = 0.36
Learn more about probability here:
brainly.com/question/1210781