
Ammar H. answered 02/11/24
Math Tutoring: Reach Your Goals!
When rolling a pair of dice, the possible outcomes for each die are 1, 2, 3, 4, 5, and 6. The probability of rolling a 5 on a single die is 1/6.
Let’s denote (X) as the number of fives rolled when two fair dice are tossed at the same time. The possible values for (X) are 0, 1, and 2.
- (X = 0): This means that neither of the dice shows a 5. The probability of not rolling a 5 on a single die is 5/6. Since the two dice are independent, the probability of not rolling a 5 on either die is ((5/6) \times (5/6) = 25/36).
- (X = 1): This means that exactly one of the dice shows a 5. There are two ways this can happen: either the first die shows a 5 and the second does not, or the first die does not show a 5 and the second does. The probability of either of these events is ((1/6) \times (5/6) = 5/36). Since there are two such events, the total probability is (2 \times (5/36) = 10/36).
- (X = 2): This means that both dice show a 5. The probability of this event is ((1/6) \times (1/6) = 1/36).
So, the probability distribution is:
X | |
0 | 25/36 |
1 | 10/36 |
2 | 1/36 |
To calculate the mean, standard deviation, and variance, we use the following formulas:
- Mean ((\mu)): (\mu = \sum x \cdot P(x)) = 0*25/36 + 1*10/36 + 2*1/36 = 1/3
Variance ((\sigma^2)): (\sigma^2 = \sum (x - \mu)^2 \cdot P(x))= (0-1/3)2 *25/36 + (1-1/3)2 *10/36 + (2-1/3)2 *1/36 = 0.2778
- Standard Deviation ((\sigma)): (\sigma = \sqrt{\sigma^2})
Substitute the values of (X) and (P(X)) into these formulas to get the mean, variance, and standard deviation.