Question

please please please help I cannot get this wrong :(

A person is chosen at random. What is the probability that the person is 55 years of age or older, given that the person received a flu shot?


Received shots : 40(ages 18-35) 70(ages 36-54) 90(ages 55+)
Did not receive shots: 60(ages 18-35) 30(ages 36-54) 10(ages 55+)

A. 0.30
B. 0.90
C. 0.33
D. 0.85
E. 0.45

Answer 1

is it A?

Answer 2

You cannot solve this problem without the age distribution.

Answer 3

there is age distribution

Answer 4

No, there isn't.
What you have is the fraction of each age group that go the shot.
You need to know what percentage of all people are in each age group.

Answer 5

I think there's a problem with the question, but maybe someone else can help you.

Answer 6

the question tells you that the person was given a shot - so that narrows it down to the first group - agreed?

Answer 7

where first group was:

Received shots : 40(ages 18-35) 70(ages 36-54) 90(ages 55+)

Answer 8

right

Answer 9

you are also told they are 55 or older in age

Answer 10

so how many people in this group are 55+?

Answer 11

90

Answer 12

correct
now how many people altogether in this group?

Answer 13

200

Answer 14

correct - so the probability is equal to?

Answer 15

ohh .45 !

Answer 16

I get it now

Answer 17

perfect! :)

Answer 18

@asnaseer
my bad, I just assumed they were percentages, because that's how I'm used to seeing these problems.

Answer 19

thanks so much

Answer 20

yw :)
@telliott99 np - we all make mistakes - that's what makes us human :)