Answer:
a) 0.2
b) 0.28
c) 0.12
d) 0.7
Step-by-step explanation:
A probability is the number of desired outcomes divided by the number of total outcomes.
We have the following table:
At Least One Tattoo No Tattoo
Age 18-29 126 324
Age 30-50 54 396
So in total, there are
126 + 324 + 54 + 396 = 900 people
(A) P(tattoo)
This is the probability that a randomly selected person has a tattoo.
Desired outcomes:
126 + 54 = 180
180 people have at least one tattoo
Total outcomes:
There are 900 people.
P(tattoo) = 180/900 = 0.2
(B) P(tattoo | age 18-29)
This the probability that a person aged 18-29 has a tattoo
Desired outcomes:
126 people aged 18-29 have tattoos
Total outcomes:
126 + 324 = 450 people aged 18-29
P(tattoo | age 18-29) = 126/450 = 0.28
(C) P(tattoo | age 30-50)
This the probability that a person aged 30-50 has a tattoo
Desired outcomes:
54 people aged 18-29 have tattoos
Total outcomes:
54 + 396 = 450 people aged 30-50
P(tattoo | age 18-29) = 54/450 = 0.12
(D) P(age 18-29 | tattoo)
The probability that a tattoed person is 18-29.
Desired outcomes:
126 tattoed people are 18-29
Total outcomes
126 + 54 = 180 tattoed people
P(age 18-29 | tattoo) = 126/180 = 0.7
