PSY 555 Homework 8

Chapter 5: #2,3,5,9

1. State
the additive and the multiplicative law of probability and give an example of
each.

2. Describe
joint probability and conditional probability and give an example of each.

3. With
regard to probability, how are discrete and continuous variables treated
differently?

4. Volunteers
coming into a blood center are such that 1 in 5 have O+ blood, 1 in 21 have O-
blood, 1 in 3 have A+ blood, and 1 in 13 have A- blood. The name of one person who previously donated
blood is randomly selected from the records of the center. What is the probability that the person
selected has:

a. O+ blood?

b.
Type O blood?

c.
Type A blood?

d.
Neither Type A nor Type O blood?

e.
Type A+ and O+ blood?

f.
Why is the probability in "e" what it is?

5. A
large group of people are examined for the presence of two physical
traits. It is thought that 40% of the
people possess trait A alone, 25% possess trait B alone, 8% possess both
traits, and the remainder possess neither trait. For each person chosen at random from this
group, find the probability that:

a. the person has neither trait.

b.
the person has at least one of the traits.

c.
the person has trait B.

d.
the person has both traits, given that he has trait A.