[jgilvin06]

5. a.The table show drinking habits of adult men and women.

Non-Drinker Occasional Drinker Regular Drinker Heavy Drinker Total
Men 387 45 90 37 559
Women 421 46 69 34 570
Total 808 91 159 71 1129

If one of the 1129 people is randomly chosen, find the probability that the person is a woman or a heavy drinker. Round your answer to the nearest 3 decimal places. (References: example 4 page 163, end of section exercises 23 - 26 page 168 - 169) (5 points)

b. The table show drinking habits of adult men and women.

Non-Drinker Occasional Drinker Regular Drinker Heavy Drinker Total
Men 387 45 90 37 559
Women 421 46 69 34 570
Total 808 91 159 71 1129

If one of the 1129 people is randomly chosen, find the probability that the person is a non-drinker or a heavy drinker. Round your answer to the nearest 3 decimal places. (References: example 4 page 163, end of section exercises 23 - 26 page 168 - 169) (5 points)

[morgaine300]

The addition rule is A + B - Intersection. It's to get the union. On a chart like this, the cross between a row and a column is an intersection because that's where someone is both. (e.g. 387 are a man AND a non-drinker. Intersection.)

Remember that OR means that it's something in either of the categories. So for the first one, if it's a woman, she might be a heavy drinker, but doesn't have to be, because it's an OR. It can also be a man who is a heavy drinker, because that's also an OR. The person can be either of the two.

So you look at how many total women you have, then the total of heavy drinkers you have. If you simply add these together, you are going to duplicate the 34, so you subtract one out. Hence, A + B - Intersection.

(Remember that only tells you how many are a woman or heavy drinker. A probability is that divided by the total.)