Chapter 5, Problem R5.5RE

a.

To determine

To find : Probability that the person drives an SUV

Answer to Problem R5.5RE

0.325

Explanation of Solution

Given information : Table that summarizes the responses of 120 people.

Cart type

	Sedan	SUV	Truck
Yes	25	15	12
No	20	24	24

Total number of people = 120

Number of persons who drive SUV = 15+24=39

So,

Probability that the person drives an SUV = (Number of persons who drive SUV) / (Total number of people) = 39/120=0.325

b.

To determine

To find : Probability that the person drives a Sedan or exercise for at least 30 minutes four or more times per week

Answer to Problem R5.5RE

0.6

Explanation of Solution

Let A denotes the event that a person who drive Sedan and B denotes the event that a person exercises for at least 30 minutes four or more times per week.

  $P(A)=\frac{25+20}{120}=\frac{45}{120}$

  $P(B)=\frac{25+15+12}{120}=\frac{52}{120}$

  $P(A\cap B)=\frac{25}{120}$

  $P(A\cup B)=P(A)+P(B)-P(A\cap B)$

  $=\frac{45}{120}+\frac{52}{120}-\frac{25}{120}$

  $=\frac{72}{120}$

  $=0.6$

c.

To determine

To find : Probability that the person does not drive a truck

Answer to Problem R5.5RE

0.6

Explanation of Solution

Number of persons who do not drive a truck =25+15=40

Total number of persons = 120

Probability that the person who does not drive a truck, given that she or he exercises for at least 30 minutes four or more times per week =40/120 =0.3