In: Statistics and Probability
Suppose you ask a friend to randomly choose an integer between 1 and 10, inclusive. What is the probability that the number will be more than 5 or odd? (Enter your probability as a fraction.)
Two dice are rolled. Determine the probability of the following. ("Doubles" means both dice show the same number.)
rolling a 4 or doubles
Use the data in the table below, which shows the employment status of individuals in a particular town by age group.
| Age | Full-time | Part-time | Unemployed |
|---|---|---|---|
| 0—17 | 27 | 170 | 358 |
| 18—25 | 199 | 199 | 272 |
| 26—34 | 342 | 71 | 22 |
| 35—49 | 521 | 175 | 238 |
| 50+ | 350 | 165 | 303 |
If a person is randomly chosen from the town's population, what is the probability that the person is under 18 or employed part-time?
Suppose you ask a friend to randomly choose an integer between 1 and 10, inclusive. What is the probability that the number will be more than 5 or odd? (Enter your probability as a fraction.)
We have 5 numbers(6,7,8,9,10) above 5 and 5 odd numbers(1,3,5,7,9) in ten numbers. The common numbers in these two are 7 and 9. So the probability that the number will be more than 5 or odd is
P(x>5 U x is odd)= P(x>5) +p(x is odd) -p(x>5
x is
odd)
=5/10+5/10-2/10
=4/5
Two dice are rolled. Determine the probability of the following. ("Doubles" means both dice show the same number.)
rolling a 4 or doubles
Probability of rolling a sum of 4 =3/36=1/12
Probability of both die showing the same number is =6/36=1/6
| Sum of two variables | ||||||
| y | ||||||
| x | 1 | 2 | 3 | 4 | 5 | 6 |
| 1 | 2 | 3 | 4 | 5 | 6 | 7 |
| 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| 5 | 6 | 7 | 8 | 9 | 10 | 11 |
| 6 | 7 | 8 | 9 | 10 | 11 | 12 |
The common numbers in these two is one.
Probability of rolling a 4 or doubles= 3/36+6/36-1/36=2/9
If a person is randomly chosen from the town's population, what is the probability that the person is under 18 or employed part-time?
| Age | Full-time | Part-time | Unemployed | Total |
| 0—17 | 27 | 170 | 358 | 555 |
| 18—25 | 199 | 199 | 272 | 670 |
| 26—34 | 342 | 71 | 22 | 435 |
| 35—49 | 521 | 175 | 238 | 934 |
| 50+ | 350 | 165 | 303 | 818 |
| Total | 1439 | 780 | 1193 | 3412 |
The probability that the person is under 18 =555/3412
The probability that the person employed part-time= 780/3412
The common numbers in these two is that the person is under 18 and employed part-time=170/3412
P(x<18 U x is employed part-time)= P(x<18 +p(x is employed
part-time) -p(x<18
x is employed
part-time)
=555/3412+780/3412-170/3412=
1165/3412