Probability

#1
A study of consumer smoking habits includes 177 people in the 18-22 age bracket (48 of whom smoke), 146 people in the 23-30 age bracket (31 of whom smoke), and 81 people in the 31-40 age bracket (28 of whom smoke). If one person is randomly selected from this sample, find the probability of getting someone who is age 18-22 or does not smoke.

is this 177/404=.49
 

JohnM

TS Contributor
#2
For this one you need to make a 2-way contingency table, then compute the probability of (age 18-22 OR does not smoke)

= P(age 18-22) + P(does not smoke) - P(age 18-22 AND does not smoke)