Question 1

A family has two children;record the genders in order of birth.

Accepted Answer

A) {BB,BG,GG},equally likely 
B) {BB,BG,GB,GG},equally likely 
C) {BB,BG,GG},not equally likely 
D) {BB,BG,GB,GG},not equally likely 
E) {B,G},equally likely

Question 2

An online poll asked people what their main source of news was: newspapers,television,internet,or radio? There were 866 responses.Here are the results: 
If we select a person at random from this sample of 912 people,what is the probability that the person responded "Internet" or "Radio"?

Accepted Answer

A) 0.114 
B) 0.669 
C) 0.331 
D) 0.217 
E) 302

Question 3

An auto insurance company was interested in investigating accident rates for drivers in different age groups.The following table was based on a random sample of drivers and classifies drivers by age group and accident rate. 
Suppose one of these people is selected at random.Compute the probability that the person is aged over 45.

Accepted Answer

A) 0.539 
B) 0.375 
C) 0.094 
D) 0.776 
E) 0.484

Question 4

Roll an ordinary die;record the number.

Accepted Answer

A) {1,2,3,4,5,6},not equally likely 
B) {1,6},equally likely 
C) {1,2,3,4},equally likely 
D) {1,6},not equally likely 
E) {1,2,3,4,5,6},equally likely

Question 5

Toss a coin three times;record the order of heads and tails.

Accepted Answer

A) {HHH,HHT,TTH,TTT},equally likely 
B) {HHH,HHT,HTH,HHT,HTT,THT,TTH,TTT},equally likely 
C) {HHH,HHT,TTH,TTT},not equally likely 
D) {H,T},equally likely 
E) {HHH,HHT,HTH,HHT,HTT,THT,TTH,TTT},not equally likely

Question 6

In a survey of women who were asked to name their favorite colour,16% said blue,19% said red,19% said green,12% said yellow,and 11% said black.If you pick a survey participant at random,what is the probability that she named a colour different from the aforementioned colours?

Accepted Answer

A) 0.16 
B) 0.23 
C) 0.77 
D) 0.20 
E) 0.82

Question 7

At a California college,17% of students speak Spanish,6% speak French,and 2% speak both languages.What is the probability that a student chosen at random from the college speaks Spanish but not French?

Accepted Answer

A) 0.11 
B) 0.13 
C) 0.21 
D) 0.15 
E) 0.04

Question 8

Roll a die and record the number.Then flip a coin and record whether it comes up heads or tails.

Accepted Answer

A) {1H,1T,2H,2T,3H,3T,4H,4T,5H,5T,6H,6T},equally likely 
B) {1H,1T,2H,2T,3H,3T,4H,4T,5H,5T,6H,6T},not equally likely 
C) {1,2,3,4,5,6,H,T},not equally likely 
D) {1H,1T,2H,2T,3H,3T,4H,4T,5H,5T,6H,6T,HH,HT,TH,TT},equally likely 
E) {1H,2T,3H,4T,5H,6T},equally likely

Question 9

Many stores run "secret sales": Shoppers receive cards that determine how large a discount they get,but the percentage is revealed by scratching off that black stuff only after the purchase has been totaled at the cash register.The store is required to reveal (in the fine print)the distribution of discounts available.Determine whether the following probability assignment is legitimate.
Probability of ...

Accepted Answer

A) Legitimate 
B) Not legitimate

Question 10

The following contingency table provides a joint frequency distribution for a group of retired people by career and age at retirement. 
Suppose one of these people is selected at random.Compute the probability that the person selected was a store clerk.

Accepted Answer

A) 0.084 
B) 0.099 
C) 0.316 
D) 0.267 
E) 0.026

Question 11

The plastic arrow on a spinner for a child's game stops rotating to point at one of four colours that will determine what happens next.Determine whether the following probability assignment is legitimate.
Probability of ...

Accepted Answer

A) Legitimate 
B) Not legitimate

Question 12

The contingency table below provides a joint frequency distribution for a random sample of patients at a hospital classified by blood type and sex. 
If a person is selected at random from the sample,find the probability that the person has blood type A or is female.

Accepted Answer

A) 0.985 
B) 0.767 
C) 0.378 
D) 0.535 
E) 0.218

Question 13

Pick cards from a deck until you get a black card or 4 consecutive red cards;record the cards in order.

Accepted Answer

A) {BBBB,RBBB,RRBB,RRRB,RRRR},not equally likely 
B) {B,RB,RRB,RRRB,RRRRB,RRRRRB,....},not equally likely 
C) {B,RB,RRB,RRRB,RRRRB},not equally likely 
D) {B,RB,RRB,RRRB,RRRR},not equally likely 
E) {BBBB,BBBR,BBRB,BBRR,BRBB,BRBR,BRRB,BRRR,RBBB,RBBR,RBRB,RBRR,RRBB,RRBR,RRRB,RRRR},equally likely

Question 14

The probability that a student at a certain college is male is 0.47.The probability that a student at that college has a job off campus is 0.22.The probability that a student at the college is male and has a job off campus is 0.12.If a student is chosen at random from the college,what is the probability that the student is male or has an off campus job?

Accepted Answer

A) 0.57 
B) 0 
C) 0.81 
D) 0.69 
E) 0.45

Question 15

The plastic arrow on a spinner for a child's game stops rotating to point at one of four colours that will determine what happens next.Determine whether the following probability assignment is legitimate.
Probability of ...

Accepted Answer

A) Legitimate 
B) Not legitimate

Question 16

Which of the following are equivalent to the probability of the complement of event A?
(i)P( 
)
(ii)1 - P(A does not occur)
(iii)1 - P(A occurs)
(iv)P(A does not occur)

Accepted Answer

A) ii 
B) i,iii,and iv 
C) i and iii 
D) i,ii,and iv 
E) iii and iv

Question 17

Employment data at a software company reveal that 41% of employees have a computer science degree,36% are women and half of the women have a computer science degree.What is the probability that a randomly chosen employee is female or has a computer science degree?

Accepted Answer

A) 0.77 
B) 0.23 
C) 0.18 
D) 0.41 
E) 0.59

Question 18

A telemarketer is almost through with her entire shift,and she has not made a single sale.Her manager says that she has a good chance of making a sale on her last few phone calls because she is due.Is her manager right?

Accepted Answer

A) No,because the Probability Assignment Rule applies in the long-run,not in the short-run. 
B) Yes,because the Law of Averages is valid for independent events. 
C) No,because there is no Law of Large Numbers for independent events. 
D) Yes,because the Law of Large Numbers is valid for independent events. 
E) No,because there is no Law of Averages for independent events.

Question 19

Many stores run "secret sales": Shoppers receive cards that determine how large a discount they get,but the percentage is revealed by scratching off that black stuff only after the purchase has been totaled at the cash register.The store is required to reveal (in the fine print)the distribution of discounts available.Determine whether the following probability assignment is legitimate.
Probability of ...

Accepted Answer

A) Legitimate 
B) Not legitimate

Question 20

In a survey of women who were asked to name their favorite colour,18% said blue,16% said red,17% said green,12% said yellow,and 14% said black.If you pick a survey participant at random,what is the probability that her favorite colour is yellow or black?

Accepted Answer

A) 0.14 
B) 0.26 
C) 0.74 
D) 0.12 
E) 0.34

Exam 13: From Randomness to Probability

A family has two children;record the genders in order of birth.

An online poll asked people what their main source of news was: newspapers,television,internet,or radio? There were 866 responses.Here are the results: If we select a person at random from this sample of 912 people,what is the probability that the person responded "Internet" or "Radio"?

Roll an ordinary die;record the number.

Toss a coin three times;record the order of heads and tails.

In a survey of women who were asked to name their favorite colour,16% said blue,19% said red,19% said green,12% said yellow,and 11% said black.If you pick a survey participant at random,what is the probability that she named a colour different from the aforementioned colours?

At a California college,17% of students speak Spanish,6% speak French,and 2% speak both languages.What is the probability that a student chosen at random from the college speaks Spanish but not French?

Roll a die and record the number.Then flip a coin and record whether it comes up heads or tails.

The following contingency table provides a joint frequency distribution for a group of retired people by career and age at retirement. Suppose one of these people is selected at random.Compute the probability that the person selected was a store clerk.

The plastic arrow on a spinner for a child's game stops rotating to point at one of four colours that will determine what happens next.Determine whether the following probability assignment is legitimate. Probability of ...

The contingency table below provides a joint frequency distribution for a random sample of patients at a hospital classified by blood type and sex. If a person is selected at random from the sample,find the probability that the person has blood type A or is female.

Pick cards from a deck until you get a black card or 4 consecutive red cards;record the cards in order.

The plastic arrow on a spinner for a child's game stops rotating to point at one of four colours that will determine what happens next.Determine whether the following probability assignment is legitimate. Probability of ...

Which of the following are equivalent to the probability of the complement of event A? (i) P( ) (ii) 1 - P(A does not occur) (iii) 1 - P(A occurs) (iv) P(A does not occur)

Employment data at a software company reveal that 41% of employees have a computer science degree,36% are women and half of the women have a computer science degree.What is the probability that a randomly chosen employee is female or has a computer science degree?

A telemarketer is almost through with her entire shift,and she has not made a single sale.Her manager says that she has a good chance of making a sale on her last few phone calls because she is due.Is her manager right?

In a survey of women who were asked to name their favorite colour,18% said blue,16% said red,17% said green,12% said yellow,and 14% said black.If you pick a survey participant at random,what is the probability that her favorite colour is yellow or black?