Question 1

There are 540 identical plastic chips numbered 1 through 540 in a box. What is the probability of reaching into the box and randomly drawing the chip numbered 505? Express your answer as a fraction or a decimal number rounded to four decimal places.

Answer

prob <- 1/540
fractions(prob)
## [1] 1/540

Question 2

Write out the sample space for the given experiment. Separate your answers using commas. When deciding what you want to put into a salad for dinner at a restaurant, you will choose one of the following extra toppings: asparagus, cheese. Also, you will add one of following meats: eggs, turkey. Lastly, you will decide on one of the following dressings: French, vinaigrette. (Note: Use the following letters to indicate each choice: A for asparagus, C for cheese, E for eggs, T for turkey, F for French, and V for vinaigrette.)

Answer

The sample space is as follows: {AEF,AEV, ATF, ATV, CEF, CEV, CTF,CTV}

Question 3

A card is drawn from a standard deck of 52 playing cards. What is the probability that the card will be a heart and not a face card? Write your answer as a fraction or a decimal number rounded to four decimal places.

Answer

Let H represent the event that the card is a heart Let NF represent the event that the card is not a face card

Notes:

  1. In a standard 52 card deck there are 12 face cards link Therefore, there are 52-12 = 40 cards that are not face cards

  2. In a standard 52 card deck there are 13 hearts.

Therefore: P(H and NF) = P(H) * P(NF)

probH <-  13/52
probNF <- 40/52
Ans3 <- probH * probNF
fractions(Ans3)
## [1] 5/26

Question 4

A standard pair of six-sided dice is rolled. What is the probability of rolling a sum less than 6? Write your answer as a fraction or a decimal number rounded to four decimal places.

Answer

36 total possibilities Less than 6: {4/1,3/2,3/1,2/3,2/2,2/1,1/4,1/3,1/2,1/1} - 10 possibities

fractions(10/36)
## [1] 5/18

Question 5

A pizza delivery company classifies its customers by gender and location of residence. The research department has gathered data from a random sample of 2001 customers. The data is summarized in the table below.

                Gender and Residence of Customers
                                         Males  Females
              Apartment                 233     208
              Dorm                      159     138
              With Parent(s)              102       280
              Sorority/Fraternity House 220     265
              Other                     250     146

What is the probability that a customer is male? Write your answer as a fraction or a decimal number rounded to four decimal places.

Answer

Total <- 233+159+102+220+250+208+138+280+265+146
Male <- 233+159+102+220+250
ProbMale <- Male/Total
fractions(ProbMale)
## [1] 964/2001

Question 6

Three cards are drawn with replacement from a standard deck. What is the probability that the first card will be a club, the second card will be a black card, and the third card will be a face card? Write your answer as a fraction or a decimal number rounded to four decimal places.

Answer

Let C be the event that the card is a club Let B be the event that the card is black Let F be the event that the card is a face card

probC <- 13/52
probB <- 26/52
probF <- 12/52

probCBF <- probC * probB * probF
fractions(probCBF)
## [1] 3/104

Question 7

Two cards are drawn without replacement from a standard deck of 52 playing cards. What is the probability of choosing a spade for the second card drawn, if the first card, drawn without replacement, was a heart? Write your answer as a fraction or a decimal number rounded to four decimal places.

Answer

Let S represent the event that a spade is drawn on second draw without replacement Let H represent the event that a heart is drawn

probH <- 13/52
probS <- 13/51
probSgivenH <- probH * probS
fractions(probSgivenH)
## [1] 13/204

Question 8

Two cards are drawn without replacement from a standard deck of 52 playing cards. What is the probability of choosing a heart and then, without replacement, a red card? Write your answer as a fraction or a decimal number rounded to four decimal places.

Let H represent the event that a heart is chosen Let R represent the event that a red card is chosen

Answer

PHandR <- 13/52 * 25/51
fractions(PHandR)
## [1] 25/204

Question 9

There are 85 students in a basic math class. The instructor must choose two students at random.

                    Students in a Basic Math Class
                                    Males   Females
                        Freshmen      12      12
                        Sophomores  19    15
                        Juniors     12    4
                        Seniors     7       4

What is the probability that a junior female and then a freshmen male are chosen at random? Write your answer as a fraction or a decimal number rounded to four decimal places.

Answer

Let JF represent the event that a Junior Female is chosen Let FM represent the event that a Freshman Male is chosen

Total <- 12+19+12+7+12+15+4+4
PJFthenFM <- 4/Total * 12/(Total-1)
fractions(PJFthenFM)
## [1] 4/595

Question 10

Out of 300 applicants for a job, 141 are male and 52 are male and have a graduate degree.

Step 1. What is the probability that a randomly chosen applicant has a graduate degree, given that they are male? Enter your answer as a fraction or a decimal rounded to four decimal places.

Step 2. If 102 of the applicants have graduate degrees, what is the probability that a randomly chosen applicant is male, given that the applicant has a graduate degree? Enter your answer as a fraction or a decimal rounded to four decimal places.

Answer Step1

Let M represent the event that the applicant is male Let G represent the event that the applicant has a graduate degree

ProbM <- 141/300
ProbGandM <- 52/300

PGgivenM <- ProbGandM/ProbM
fractions(PGgivenM)
## [1] 52/141

Answer Step2

ProbG <- 102/300
PMgivenG <- ProbGandM/ProbG
fractions(PMgivenG)
## [1] 26/51

Question 11

A value meal package at Ron’s Subs consists of a drink, a sandwich, and a bag of chips. There are 6 types of drinks to choose from, 5 types of sandwiches, and 3 types of chips. How many different value meal packages are possible?

Answer

Ans <- 6 * 5 * 3
Ans
## [1] 90

Question 12

A doctor visits her patients during morning rounds. In how many ways can the doctor visit 5 patients during the morning rounds?

Answer

Ans <- factorial(5)
Ans
## [1] 120

Question 13

A coordinator will select 5 songs from a list of 8 songs to compose an event’s musical entertainment lineup. How many different lineups are possible?

Answer

Assume order of lineup is important.

nrow(permutations(8,5))
## [1] 6720

Question 14

A person rolls a standard six-sided die 9 times. In how many ways can he get 3 fours, 5 sixes and 1 two?

Answer

Ans <- 3 * 5 * 1
Ans
## [1] 15

Question15

How many ways can Rudy choose 6 pizza toppings from a menu of 14 toppings if each topping can only be chosen once?

Answer

nrow(combinations(14,6))
## [1] 3003

Question 16

3 cards are drawn from a standard deck of 52 playing cards. How many different 3-card hands are possible if the drawing is done without replacement?

Answer

nrow(combinations(52,3))
## [1] 22100

Question 17.

You are ordering a new home theater system that consists of a TV, surround sound system, and DVD player. You can choose from 12 different TVs, 9 types of surround sound systems, and 5 types of DVD players. How many different home theater systems can you build?

Answer

Ans <- 12 * 9 * 5
Ans
## [1] 540

Question 18.

You need to have a password with 5 letters followed by 3 odd digits between 0 - 9 inclusively. If the characters and digits cannot be used more than once, how many choices do you have for your password?

Answer

Assume letters must be lowercase only Letters - there are 26 letters Digits - there are 5 odd digits between 0 and 9 (1,3,5,7,9)

Letters <- nrow(permutations(26,5))
Digits <- nrow(permutations(5,3))

Password <- Letters * Digits
Password
## [1] 473616000

Question 19

Evaluate the following expression.9P4

Answer

Ans <- nrow(permutations(9,4))
Ans
## [1] 3024

Question 20

Evaluate the following expression. 11C8

Answer

Ans <- nrow(combinations(11,8))
Ans
## [1] 165

Question 21

Evaluate the following expression. (12P8)/( 12C4)

Answer

Ans <- (nrow(permutations(12,8))/nrow(combinations(12,4)))
Ans
## [1] 40320

Question 22

The newly elected president needs to decide the remaining 7 spots available in the cabinet he/she is appointing. If there are 13 eligible candidates for these positions (where rank matters), how many different ways can the members of the cabinet be appointed?

Answer

nrow(permutations(13,7))
## [1] 8648640

Question 23

In how many ways can the letters in the word ‘Population’ be arranged?

Answer

Ans <- factorial(10)
Ans
## [1] 3628800

Question 24

Consider the following data:

x 5 6 7 8 9 p(x) 0.1 0.2 0.3 0.2 0.2

Step 1. Find the expected value E( X ). Round your answer to one decimal place.
Step 2. Find the variance. Round your answer to one decimal place. Step 3. Find the standard deviation. Round your answer to one decimal place. Step 4. Find the value of P(X >= 9). Round your answer to one decimal place. Step 5. Find the value of P(X <= 7). Round your answer to one decimal place.

Answer

x <- c(5,6,7,8,9)
p <- c(0.1,0.2,0.3,0.2,0.2)

step1 <- round(sum(x*p),1)
step1
## [1] 7.2
step2 <- round(((sum(x^2 * p)) - step1^2),1)
step2
## [1] 1.6
step3 <- round(sqrt(step2),1)
step3
## [1] 1.3
step4 <- 0.2
step4
## [1] 0.2
step5 <- 0.1+0.2+0.3
step5
## [1] 0.6

Question 25.

Suppose a basketball player has made 188 out of 376 free throws. If the player makes the next 3 free throws, I will pay you $23. Otherwise you pay me $4.

Step 1. Find the expected value of the proposition. Round your answer to two decimal places.

Step 2. If you played this game 994 times how much would you expect to win or lose? (Losses must be entered as negative.)

Answer

Let X represent the event that the number of free throws made by the basketball player : x ~ B(3,188/376)

Step1: Expected Value

Ans <- 3 * 188/376
round(Ans,2)
## [1] 1.5

Step2: Expected Wins or Losses:

probLoss <- pbinom(2, size=3, prob=188/376)
probWin <- dbinom(3, size=3, prob=188/376)

Losses <- -4 * probLoss*994
Wins <- 23*probWin * 994

Winnings <- Losses + Wins
Winnings
## [1] -621.25

Question 26

  1. Flip a coin 11 times.  If you get 8 tails or less, I will pay you $1.  Otherwise you pay me $7.

Step 1. Find the expected value of the proposition. Round your answer to two decimal places.

Step 2. If you played this game 615 times how much would you expect to win or lose? (Losses must be entered as negative.)

Answer

Let X represent the number of tail tossed : x ~ B(11,1/2)

Step1: Expected Value

Ans <- 11 * 1/2
round(Ans,2)
## [1] 5.5

Step2: Expected Wins or Losses:

probLoss <- pbinom(8, size=11, prob=1/2, lower.tail = FALSE)
probWin <- dbinom(8, size=11, prob=1/2)

Losses <- -7 * probLoss*615
Wins <- 1*probWin * 615

Winnings <- Losses + Wins
Winnings
## [1] -91.28906

Question 27

If you draw two clubs on two consecutive draws from a standard deck of cards you win $583. Otherwise you pay me $35. (Cards drawn without replacement.)

Step 1. Find the expected value of the proposition. Round your answer to two decimal places.

Step 2. If you played this game 632 times how much would you expect to win or lose? (Losses must be entered as negative.)

Answer

Since cards are drawn without replacement the distribution is hypergeometric

Expected Value:

n <- 2
k <- 13
N <- 52

Evalue <- (n*k)/N
round(Evalue,2)
## [1] 0.5

Earnings

pWin <- dhyper(2,13,39,2)
pLoss <- 1 - pWin
Winnigs <- 583*pWin*615 + (-35)*pLoss*615
Winnings
## [1] -91.28906

Question 28

  1. A quality control inspector has drawn a sample of 10 light bulbs from a recent production lot.  If the number of defective bulbs is 2 or less, the lot passes inspection.  Suppose 30% of the bulbs in the lot are defective.  What is the probability that the lot will pass inspection? (Round your answer to 3 decimal places)

Answer

Question 29

A quality control inspector has drawn a sample of 5 light bulbs from a recent production lot. Suppose that 30% of the bulbs in the lot are defective. What is the expected value of the number of defective bulbs in the sample? Do not round your answer.

Answer

Expected Value:

Ans <- 5 * 0.3
Ans
## [1] 1.5

Question 30

The auto parts department of an automotive dealership sends out a mean of 5.5 special orders daily. What is the probability that, for any day, the number of special orders sent out will be more than 5? (Round your answer to 4 decimal places)

Answer

round(ppois(5, lambda = 5.5, lower.tail = FALSE),4)
## [1] 0.4711

Question 31

At the Fidelity Credit Union, a mean of 5.7 customers arrive hourly at the drive-through window. What is the probability that, in any hour, more than 4 customers will arrive? (Round your answer to 4 decimal places)

Answer

round(ppois(4, lambda = 5.7, lower.tail = FALSE),4)
## [1] 0.6728

Question 32

  1. The computer that controls a bank's automatic teller machine crashes a mean of  0.4 times per day. What is the probability that, in any 7-day week, the computer will crash no more than 1 time? (Round your answer to 4 decimal places)

Answer

round(ppois(1, lambda = 2.8),4)
## [1] 0.2311

Question 33

A town recently dismissed 8 employees in order to meet their new budget reductions. The town had 6 employees over 50 years of age and 19 under 50. If the dismissed employees were selected at random, what is the probability that more than 1 employee was over 50? Write your answer as a fraction or a decimal number rounded to three decimal places.

Answer

Question 34

  1. Unknown to a medical researcher, 10 out of  25 patients have a heart problem that will result in death if they receive the test drug.  Eight patients are randomly selected to receive the drug and the rest receive a placebo.  What is the probability that less than 7 patients will die?  Write your answer as a fraction or a decimal number rounded to three decimal places.