A white and a colored die are tossed. The possible outcomes are shown in the illustration below.
(a) Identify the events A = [ Sum = 6 ],
B = [ Sum = 7], C = [ Sum is even ],
D = [ Same number on each die ].
(b) If both die are "fair," assign probability to each elementary outcome.
(c) Obtain P(A ), P(B ), P( C), P(D ).
> An insurance company's records of 12,299 automobile insurance policies revealed that 2073 made a claim. Among insured drivers under age 25, there were 1032 claims out of 5192 policies (courtesy of J. Hickman). Assuming the claim history is valid for the
> Referring to Exercise 2.20, construct a density histogram using the intervals (6.5, 6.7], (6.7, 6.9], (6.9, 7.1], (7.1, 7.5], and (7.5, 7.9]. Using R: With the observations in x hist(x,breaks= c(6.5,6. 7,6.9, 7.1, 7.5, 7 .9),prob=T) Data from Exercise 2
> One type of passenger airplane has four engines but it can still fly with only one. Suppose each engine has probability .002 of failing during a flight. (a) Calculate the probability of all four engines failing during the same flight. Assume independenc
> An urn contains two green balls and three red balls. Suppose two balls will be drawn at random one after another and without replacement (i.e., the first ball drawn is not returned to the urn before the second one is drawn). (a) Find the probabilities o
> Records of student patients at a dentist's office concerning fear of visiting the dentist suggest the following proportions. For a student selected at random, consider the events A = [ Fear ] M = [ Middle school ] (a) Find the probabilities P(A) P(AM
> For two events A and B, the following probabilities are given. P(A) = .35 P(B) = .30 P(A | B) = .6 Use the appropriate laws of probability to calculate (a) P(A¯) (b) P( AB ) (c) P(A U B)
> A witness identified a suspect as having blond hair. However, when tested under lighting conditions similar to those on the night of the incident, it was concluded that the probability of correctly identifying blond h air is .80 and the probability of be
> Th e following data relate to the proportions in a population of drivers. A = Defensive driver training last year B = Accident in current year The probabilities are given in the accompanying Venn diagram. Find P( B I A ). Are A and B independent?
> Refer to Exercise 4.39. Find (a) The conditional probability that B occurs given that A occurs. (b) The conditional probability that B does not occur given that A occurs. (c) The conditional prob ability that B occurs given that A does not occur. Dat
> A person is randomly selected from persons working in your state. Consider the two events A = [Lawyer] B = [ Driving a new luxury car ] Given that the person selected drives a new luxury car, would you expect the probability of A to be larger, the same,
> Identify these events in Exercise 4.4. (a) Not more than one correct identification. (b) Less accidents than last year. (c) Longer than the 90-day warranty but less than 425.4 days. Data from Exercise 4.4: Construct a sample space for each of the fol
> A person is randomly selected from persons working in your state. Consider the two events A = [ Earned over $70,000 last year] B = [ College graduate ] Given that the person is a college graduate, would you expect the probability of A to be larger, th
> In a recent year, 35 sites around the world experienced earthquakes of magnitude greater than 6.5. Construct a histogram using equal-length intervals starting with (6.5, 6.8], where the right-hand endpoint is included but not the left-hand endpoint.
> A social networking site reported the number of passwords memorized by 150 visitors who agreed to participate. Identify the statistical population and the sample for the number of passwords memorized.
> The following frequency table shows the classification of 58 landfills in a state according to their concentration of the three hazardous chemicals arsenic, barium, and mercury. If a landfill is selected at random, find the probability that it has: (a)
> The medical records of the male diabetic patients reporting to a clinic during one year provide the following percentages. Suppose a patient is chosen at random from this group, and the events A , B, and C are defined as follows. A = [ He has a serious c
> Given that the probability that A occurs is .3, the probability that B does not occur is .6, and the probability that either A or B occurs is .5, find: (a) The probability that A does not occur. (b) The probability that both A and B occur. (c) The pro
> Of 18 fast food restaurants in a city, 7 are in violation of sanitary standards, 8 are in violation of safety standards, and 4 are in violation of both. If a fast food restaurant is chosen at random, what is the probability that it is in compliance with
> In a class of 32 seniors and graduate students, 20 are men and 12 are graduate students of whom 8 are women . If a student is randomly selected from this class, what is the probability that the selected student is (a) a senior7 (b) a male graduate studen
> From the probabilities shown in this Venn diagram, determine the probabilities of the following events. (a) A does not occur. (b) A occurs and B does not occur. (c) Exactly one of the events A and B occurs.
> If P(A) = .4 and P(B) = .7, can A and B be mutually exclusive? Why or why not ?
> Binge drinking for males is consuming 5 drinks in two hours and for females it is consuming 4 drinks. Consider the two events A = [ Binge drinking ] B = [Female ] A recent survey by the National Center for Health Statistics suggests the probabilities
> Refer to Exercise 4.39. Express the following events in set notation and find their probabilities. (a) B occurs and A does not occur. (b) N either A nor B occurs. (c) Either A occurs or B does not occur. Data from Exercise 4.39: Consider the two even
> Construct a sample space for each of the following experiments. (a) Someone claims to be able to taste the difference between the same brand of bottled, tap, and canned draft beer. A glass of each is poured and given to the subject in an unknown order.
> A zoologist collected wild lizards in the Southwestern United States. Thirty lizards from the genus Phrynosoma were placed on a treadmill and their speed measured. The recorded speed (meters/second) is the fastest time to run a half meter (courtesy of K.
> Consider the two events. A = [Obese] B = [Male] for persons in the age group 20-39 years old. A recent survey by the National Center for Health Statistics suggests the probabilities P(A) = .36 P(B) = .50 P(AB) = .18 for a randomly selected person. (a
> Refer to Exercise 4.31. Suppose the elementary outcomes are assigned these probabilities. (a) Find P(A), P(B),and P(AB). (b) Employing the laws of probability and the results of part (a), calculate P(A¯) and P( A U B). (c) Verify your answe
> A sample space consists of 9 elementary outcomes e1, e2 , … , e9 whose probabilities are Suppose (a) Calculate P(A), P(B), and P(AB). (b) Using the addition law of probability, calculate P( A U B). (c) List the composition of the ev
> For the experiment of Exercise 4.35, give a verbal description of each of the following events and also state the composition of the event. (a) C¯ (b) CA (c) A U C¯ Data from Exercise 4.35: Four applicants are interviewed for an administrative position
> Four applicants are interviewed for an administrative position with an environmental lobby. They have the following characteristics. 1. Psychology major, male, GPA 3 .5 2. Chemistry major, fem ale, GPA 3.3 3. Journalism major, female, GPA 3.7 4. Mathemat
> Suppose you have h ad interviews for summer jobs at a grocery store, a discount store, and a movie theater. Let G, D, and M denote the events of your getting an offer from the grocery store, the discount store, and the movie theater, respectively. Expres
> Refer to Exercise 4.32. Corresponding to each verbal description given here, write the event in set notation, give its composition, and find its probability. (a) C does not occur. (b) Both A and B occur. (c) A occurs and B does not occur. (d) Neither
> A sample space consists of 8 elementary outcomes with the following probabilities. P(e1) = .07 P(e2) = P(e3) = P(e4) = .11 P(e5) = P (e6) = P (e7) = P (e8) = .15 Three events are given as A { e1, e2 , e6 , e7 }, B { e2, e3, e7 ), and C = {e6 , e8). (a)
> Next week, a student worker will be assigned one morning of kitchen duty. The sample space has seven elementary outcomes e1 , e2, .. , e7 where e1 represents Sunday, e2 Monday, and so on. Two events are given as A = {e4 , e5, e6 , e7) and B = {e1, e6 , e
> Refer to Exercise 4.24. Using relative frequencies to estimate probabilities, find which 3 consecutive months have the lowest probability of a new birth. Data from Exercise 4.24: (a) Consider the simplistic model that human births are evenly distributed
> Tornadoes kill many people every year in the United States. The yearly number of lives lost during the 50 years 1962 through 2011 are summarized in the following table. (a) Calculate the relative frequency for the intervals [0, 25), [25, 50) and so on wh
> Identify the statement that best describes each P (A). (a) P(A) = .04 (i) P(A) is incorrect. (b) P(A) = .36 (ii)A rarely occurs. (c) P(A) = -.5 (iii) A occurs moderately often.
> Refer to Exercise 4.28. (a) Assign probabilities to the elementary outcomes. (b) Find P (A) and P (B) . Data from Exercise 4.28: A local bookstore intended to award three gift certificates in the amounts $100, $50, and $25 to the first, second, and th
> A local bookstore intended to award three gift certificates in the amounts $100, $50, and $25 to the first, second, and third customer to identify a mystery author. Unfortunately, a careless clerk in charge of mailing forgot the order and just randomly p
> A random selection of 1000 smartphone owners, ages 18-24 years old, were asked if they constantly check and use their phone. A total of 518 responded yes. (a) Estimate the probability that, a smartphone owner in that age group constantly checks or uses
> A plant geneticist crosses two parent strains, each with gene pairs of type aA. An offspring receives one gene from each parent. (a) Construct the sample space for the genetic type of the offspring. (b) Assign probabilities assuming that the selection o
> A government agency will randomly select one of the 14 paper mills in a state to investigate its compliance with federal safety standards. Suppose, unknown to the agency, 9 of these mills are in compliance, 3 are borderline cases, and 2 are in gross viol
> (a) Consider the simplistic model that human births are evenly distributed over the 12 calendar months. If a person is randomly selected, say, from a phone directory, what is the probability that his or her birthday would be in November or December? (b)
> Campers arriving at a summer camp will be asked one after another whether they have protection against Lyme disease M or not (N). The inspection will continue until one camper is found to be not protected or until five campers are checked, whichever occu
> Friends will be called, one after another, and asked to go on a weekend trip with you. You will call until one agrees to go (A) or four friends are asked, whichever occurs first. List the sample space for the number of calls.
> Fifteen persons reporting to a Red Cross center one day are typed for blood, and the following counts are found: If one person is randomly selected, what is the probability that this person's blood group is: (a) AB? (b) Either A or B? (c) Not O?
> According to the cause-and-effect diagram, where are the possible delays on the first floor?
> Birth rates in the 50 states, collected in a recent year by the Center for Health Statistics, are grouped into the following frequency table. Endpoint convention: Lower endpoint is included, upper endpoint is not. If one state is selected at random, what
> For each numerical value assigned to the probability of an event, identify the verbal statements that are appropriate. (a) 1.1 (b) 1/1.1 (c) 1/2 (d) 43/47 (e) 1/89 (f) 1.0 Verbal statements: (i) cannot be a probability, (ii) the event is very unlikely to
> Suppose you are eating at a pizza parlor with two friends. You have agreed to the following rule to decide who will pay the bill. Each person will toss a coin. The person who gets a result that is different from the other two will pay the bill. If all th
> A stack contains eight tickets numbered 1, 1, 2, 2, 2, 3, 3, 3 . One ticket will be drawn at random and its number will be noted. (a) List the sample space and assign probabilities to the elementary outcomes. (b) What is the probability of drawing an od
> A letter is chosen at random from the word "CHEERFUL." What is the probability that it is a vowel?
> Consider the experiment of tossing a fair coin three times. (a) List the sample space by drawing a tree diagram. (b) Assign probabilities to the elementary outcomes. (c) Find the probability of getting exactly one head.
> Among 41, 131 turkey permit holders for a recent hunting season in Wisconsin, 8845 harvested a bird. Assuming conditions are the same today, estimate the prob ability that a turkey will be harvested for a single permit.
> Refer to the day of birth data. Assuming conditions are the same today, estimate the probability that a baby will be born during a weekday. That is, not on Saturday or Sunday.
> The probability of an event is often expressed in terms of odds. Specifically, when we say that the odds are k to m that an event will occur, we mean that the probability of the event is k / ( k + m). For instance, "the odds are 4 to 1 that candidate Jon
> How many of the calls in the initial data set took over 125 minutes to answer? H ow many over 90 minutes?
> A campus organization will select one day of the week for an end-of-year picnic. Assume that the weekdays, Monday through Friday, are equally likely and that each weekend day, Saturday and Sunday, is twice as likely as a weekday to be selected. (a) Assi
> Suppose S = {e1, e2, e3}. If the simple events e1, e2, and e3 are all equally likely, what are the numerical values P(e1), P(e2) , and P(e3)?
> Match the proposed probability of A with the appropriate verbal description. (More than one description may apply.)
> Typically, there is a gender unbalance among tenured faculty, especially in the sciences. At a large university, tenured faculty members in two departments, English and Computer Science, were categorized according to gender. (a) Calculate relative freque
> A psychologist interested in obese children gathered data on a group of children and their parents. (a) Calculate the marginal totals. (b) Convert the frequencies to relative frequencies. (c) Calculate the relative frequencies separately for each row.
> Cross-tabulate the "Class data" according to gender (M, F) and the general areas of intended major (H, S, B, P). Calculate the relative frequencies.
> Interviews with 150 persons engaged in a stressful occupation revealed that 57 were alcoholics, 64 were mentally depressed, and 42 were both. (a) Based on these records, complete the following two-way frequency table. (b) Calculate the relative frequen
> Groundwater from 19 wells was classified as low or high in alkalinity and low or high in dissolved iron. There were 9 wells with high alkalinity, 7 that were high in iron, and 5 that were high in both. (a) Based on these data, complete the following two-
> The amount of municipal solid waste created has become a major problem . According to the Environmental Protection Agency, the yearly amounts (millions of tons) are: (a) Plot the amount of garbage (millions of tons) versus population (millions). (b) Fit
> Refer to data on the wolf population in Wisconsin. (a) Fit a least squares line to summarize the growth. (b) Does your fitted straight line summarize the growth in the wolf population over this period of time? If so, what numerical value summarizes the
> Give a statement of purpose for determining the amount of time it takes to make hotel reservations in San Francisco using the internet.
> In an experiment to study the relation between the time waiting in line, y (minutes), to get to the head of the checkout line at her favorite grocery store and the number of persons ahead in line, x, a student collected the following statistics: (a) Find
> For the data set (a) Construct a scatter diagram. (b) From a visual inspection, draw a straight line that appears to fit the data well. (c) Calculate the least squares estimates and draw the least squares fitted line on your plot.
> A survey was conducted to study the attitudes of the faculty, academic staff, and students in regard to a proposed measure for reducing the heating and air-conditioning expenses on campus. Compare the attitude patterns of the three groups by computing th
> Given these five pairs of ( x, y ) values (a) Construct a scatter diagram. (b) From a visual inspection, draw a straight line that appears to fit the data well. (c) Compute the least squares estimates β^o and β^1 and draw the fi
> Identify the predictor variable x and the response variable y in each of the following situations. (a) A training director wishes to study the relationship between the duration of training for new recruits and their performance in a skilled job. (b) Th
> A store manager has determined that the monthly profit y realized from selling a particular brand of car battery is given by y = 10x – 155 where x denotes the number of these batteries sold in a month. (a) If 41 batteries were sold in a month, what was t
> Plot the line y = 4 - 2x by locating the points for x = 0 and x = 3. What is its intercept? Its slope?
> Plot the line y = 2 + 3x by locating points for x = and x = 4. What is its intercept? Its slope?
> Refer to the data on garbage in Exercise 3.31. (a) Calculate the correlation coefficient between the amount of garbage in millions of tons and the population size in millions. (b) Based on your calculation in part (a), give the correlation coefficient
> Refer to the data on garbage in Exercise 3.31. (a) Replace the year by (year - 1970). Calculate the correlation coefficient between (year - 1970) and amount of garbage in millions of tons. (b) Based on your calculation in part (a), what is the correlat
> Give a statement of purpose for a study to determine the favorite campus area pizza establishment.
> Refer to the data on garbage in Exercise 3.31 . (a) Plot the amount of garbage (millions of tons) versus population (millions). (b) Does there appear to be a strong correlation? Explain. (c) H ow does your interpretation of the association differ from
> The amount of municipal solid waste created has become a major problem. According to the Environmental Protection Agency, the yearly amounts (millions of tons) are: (a) Plot the amount of garbage ( millions of tons) versus year. (b) Visually, does there
> Suppose all x measurements are changed to x' = ax + b and all y measurements to y' = cy + d, where a, b, c, and d are fixed numbers (a ≠0, c ≠0). Then the correlation coefficient remains unchanged if a and c have the
> At the conclusion of one semester, a sample of 250 juniors was questioned about how long they studied for each of their final exams. Students were also classified as social, biological, or physical science majors. Compare the times studying for finals by
> Refer to concerning spurious correlation. Replace number of smartphones with per capita soda consumption in gallons. (a) Create a scatter diagram and identify the kind of association. (b) Comment on possible lurking variables.
> An ongoing study of wolves is being conducted at the Yukon-Charley Rivers National Preserve. Table in the Data Bank gives the physical characteristics of wolves that were captured. (a) Plot length versus weight for the female wolves. From your visual ins
> An ongoing study of wolves is being conducted at the Yukon-Charley Rivers National Preserve. Table in the Data Bank gives the physical characteristics of wolves that were captured. (a) Plot length versus weight for the male wolves. From your visual inspe
> A zoologist collected 20 wild lizards in the southwestern United States. After measuring their total length (mm), they were placed on a treadmill and their speed (m/sec) recorded. (a) Create a scatter plot. Comment on any unusual observations. (b) Calcu
> The Department of Natural Resources in Wisconsin monitors air quality in the state. Ozone is a major component of smog and high temperatures also contribute. The summer maximum daily ozone (ppm) and temperature for 23 Wednesdays during two summers are Ca
> Over the years, a traffic officer noticed that cars with fuzzy dice hanging on the rear-view mirror always seemed to be speeding. Perhaps tongue in cheek, he suggest ed that outlawing the sale of fuzzy dice would reduce the number of cars exceeding the
> What is wrong with this statement of purpose? PURPOSE: Determine if a new style wireless mouse is comfortable. Give an improved statement of purpose.
> Calculations from a data set of n = 36 pairs of ( x, y) values have provided the following results. Obtain the correlation coefficient.
> Is the correlation in Figure 9 about (a) .1, (b) .5, (c) .9, or (d) -.7?
> Match the following values of r with the correct diagrams. (a) r - .3 (b) r .l (c) r .9
> (a) Construct scatter diagrams of the data sets (b) Calculate r for the data set (i). (c) Guess the value of r for the data set (ii) and then calculate r.
> Breakfast cereals from three leading manufacturers can be classified either above average or below average in sugar content. Data for ten cereals from each manufacturer are given below: (a) Complete the marginal totals. (b) Calculate the relative freque
> Refer to the alligator data of the Data Bank. Using the data on x3 and x4 for male and female alligators from Lake Apopka: (a) Make a scatter diagram of the pairs of concentrations for the male alligators. Calculate the sample correlation coefficient.
> For the data set (a) Construct a scatter diagram. (b) Guess the sign and value of the correlation coefficient. (c) Calculate the correlation coefficient.
> If the value of r is small, can we conclude that there is not a strong relationship between the two variables?
> A new study is widely reported to show that dog owners benefit by being more agreeable and extroverted than cat owners. Comment in light of facts that, on average, dogs cost more to maintain and that dog owners have larger incomes than cat owners.
> In each of the following instances, would you expect a positive, negative, or zero correlation? (a) Number of salespersons and total dollar sales for real estate firms. (b) Total payroll and percent of wins of national league baseball teams. (c) The amou