Question

A health study tracked a group of person for five years. At the beginning of the study, 20% were classified as heavy smokers, 30% as light smokers, and 50% as nonsmokers. Results of the study showed that light smokers were twice as likely as nonsmokers to die during the five-year study, but only half as likely as heavy smokers. A randomly selected participant from the study died during the five-year period. Calculate the probability that the participant was a heavy smoker. g

Answer 1

Answer: 0.421

Explanation:

Heavy smoker = 20%

Light smoker = 30%

Non smokers = 50%

We can assume that the probability that a non-smoker is going to die in the next 5 years be y.

Since light smokers were twice as likely as nonsmokers to die during the five-year study, the probability will be:

= 2 × y = 2y

Probability for the Heavy smokers will be:= 2 × 2y = 4y

The expected number of people that will die for each in the next 5 years will be:

Non smoker:

= 50% × y

= 0.5 × y

= 0.5y

Light smoker:

= 30% × 2y

= 0.3 × 2y.

= 0.6y

Heavy smoker:

= 20% × 4y.

= 0.2 × 4y

= 0.8y

Total = 0.5y + 0.6y + 0.8y = 1.9y

The probability that the participant was a heavy smoker will be:

= 0.8y/1.9y

= 0.421