The scatterplot shows the median starting salaries and the median mid-career salaries for graduates at a selection of colleges. (Source: The Wall Street Journal, Salary increase by salary type,
http://online.wsj.com/public/resources/documents/info-Salaries_for_Colleges_by_Typesort. html. Accessed via StatCrunch. Owner: Webster West)
a. As the data are graphed, which is the independent and which the dependent variable?
b. Why do you suppose median salary at a school is used instead of the mean?
c. Using the graph, estimate the median mid-career salary for a median starting salary of $60,000.
d. Use the equation to predict the median mid-career salary for a median starting salary of $60,000.
e. What other factors besides starting salary might influence mid-career salary?
> Assume a person is selected randomly from the group of people represented in the table in exercise 5.41. The probability the person says “Hasn’t Gone Far Enough” given that the person is a woman is 57/100 or 57%. The probability that person is a woman gi
> Refer to the table in Exercise 5.41. Suppose a person is randomly selected from this group. Is being female independent of answering “Hasn’t Gone Far Enough”?
> Ring sizes typically range from about 3 to about 14. Based on what you know about gender differences, if we randomly select a person, are the event that the ring size is smaller than 5 and the event that the person is a male independent or associated? Ex
> The 2017 World Almanac and Book of Facts reported that in 2016, M&Ms had sales of approximately $3.48 million and that this accounted for 12.95% of the total chocolate candy sales. What was the total amount of chocolate candy sales?
> Suppose a person is chosen at random. Use your knowledge about the world to decide whether the event that the person has brown eyes and the event that the person is female are independent or associated. Explain.
> About 12% of men and 10% of women are left-handed. If we select a person at random, are the event that the person is male and the event that the person is left-handed independent or associated?
> Suppose a person is chosen at random. Use your understanding about the world of basketball to decide whether the event that the person is taller than 6 feet and the event that the person plays professional basketball are independent or associated. Explai
> Use the data in exercise 5.43 for this problem. Note: Your answers to each of these three questions should not be the same. a. Find the probability that a randomly selected person did not have a child under 18 years old, given that they said No. b. Find
> A Gallup poll asked people with and without children under 18 years old if they frequently experienced stress. The results are shown in the table below. (Source: Gallup.com) a. Find the probability that a randomly chosen person from this group said &aci
> A driving exam consists of 30 multiple-choice questions. Each of the answers is either right or wrong. Suppose that the probability of making fewer than 7 mistakes is 0.23 and the probability of making from 7 to 15 mistakes is 0.41. Find the probability
> An exam consists of 12 multiple-choice questions. Each of the 12 answers is either right or wrong. Suppose the probability a student makes fewer than 3 mistakes on the exam is 0.48 and the probability that a student makes from 3 to 8 (inclusive) mistakes
> When a certain type of thumbtack is tossed, the probability that it lands tip up is 60%, and the probability that it lands tip down is 40%. All possible outcomes when two thumbtacks are tossed are listed. U means the tip is Up, and D means the tip is Dow
> When a certain type of thumbtack is tossed, the probability that it lands tip up is 60%. All possible outcomes when two thumbtacks are tossed are listed. U means the tip is up, and D means the tip is down. UU … UD … DU … DD a. What is the probability of
> A 2018 Pew poll asked U.S. adults how often they go online. The responses are shown in the table. a. What percentage of respondents go online less than once a day? b. In a group of 500 U.S. adults, how many would you expect go online almost constantly o
> The 2017 World Almanac and Book of Facts reported that the U.S. occupation projected to grow the most is personal care aide. By 2024 there will be a need for 160,328 personal care aides, a growth of about 26% over 2014 levels. How many personal care aide
> A 2018 Marist poll asked respondents what superpower they most desired. The distribution of responses are shown in the table. a. What percentage of those surveyed wanted to be able to fly or teleport? b. If there were 1200 people surveyed, h
> Political science researchers often classify voters according to their political party preference, using four categories: Democrat, Republican, Other political parties (including Libertarians and Independents, for example), and Decline to State/No Party
> A college conducted a student survey to learn about commute patterns. Students were given a choice of three options: car, bus, or other. When looking at the survey results, 42% of students responded “car,” and 23% responded “bus.” Assuming all students a
> One of the authors did a survey to determine the effect of students changing answers while taking a multiple-choice test on which there is only one correct answer for each question. Some students erase their initial choice and replace it with another. It
> Assume that the only grades possible in a history course are A, B, C, and lower than C. The probability that a randomly selected student will get an A in a certain history course is 0.18, the probability that a student will get a B in the course is 0.25,
> Roll a fair six-sided die. a. What is the probability that the die shows an even number or a number less than 4 on top? b. What is the probability the die shows an odd number or a number greater than 4 on top?
> Roll a fair six-sided die. a. What is the probability that the die shows an even number or a number greater than 4 on top? b. What is the probability the die shows an odd number or a number less than 3 on top?
> Refer to the table in exercise 5.19. Suppose we select one person at random from this group. Name a pair of events that are not mutually exclusive.
> Referring to the table given in exercise 5.19, name a pair of mutually exclusive events that could result when one person is selected at random from the entire group.
> Suppose a person is selected at random from a large population. a. Label each pair of events as mutually exclusive or not mutually exclusive. i. The person has traveled to Mexico; the person has traveled to Canada. ii. The person is single; the person is
> Make a two-way table from Table 1 for gender and hair color. Put the labels Male and Female across the top and Brown, Black, Blonde, and Red and then tally the data. a. Report how many are in each cell. b. Find the sums of each row and column and the gr
> Suppose a person is selected at random from a large population. a. Label each pair of events as mutually exclusive or not mutually exclusive. i. The person has traveled to Mexico; the person has traveled to Canada. ii. The person is single; the person is
> Use the data in exercise 5.23 to answer the following: a. What is the probability that a randomly selected person is a woman and said “more.” b. What is the probability that a randomly selected person is a woman or said “more” (or both)?
> A Pew Research poll asked respondents to fill in the blank to this question:Â Compared to other industries there is _____ discrimination against women in the tech industry. Responses separated by gender are shown in the following table. The re
> Use the data in exercise 5.21 to answer the following: a. If a person is chosen randomly from this group, what is the probability that the person is an Independent and said “Yes”? b. If a person is chosen randomly from this group, what is the probability
> A Gallup poll asked a sample of voters if marijuana should be legalized. Voters’ responses and political party affiliation are in the table. (Source: Gallup.com) a. If a person is randomly selected from this group, find the probability
> The Pew Research Center asked a sample of adults if they had read a book in any format in the previous 12 months. The results are shown in the table. (Source: Pewinternet.org) a. If a person is randomly selected from this group, find the probability of
> The Gallup poll asked respondents if they had taken a vacation in the last year. The respondents were separated into two groups: those who had graduated from college and those who had not. Numbers in the table are based on sample sizes of 250 in each gro
> If one card is selected from a well-shuffled deck of 52 cards, what is the probability that the card will be a club OR a diamond OR a heart? What is the probability of the complement of this event? (Refer to exercise 5.11 for information about cards.)
> What is the probability that a baby will be born on a Friday OR a Saturday OR a Sunday if all the days of the week are equally likely as birthdays?
> The sample space shows all possible sequences of child gender for a family with 3 children. The table is organized by the number of girls in the family a. How many outcomes are in the sample space? b. If we assume all outcomes in the sample space are eq
> Make a two-way table from Table 1A for gender and living situation. Put the labels Male and Female across the top and Dorm and Commuter on the side and then tally the data. See page 38 for guidance. a. Report how many are in each cell. b. Find the sums
> The sample space given here shows all possible sequences for tossing a fair coin 4 times. The sequences have been organized by the number of tails in the sequence. a. How many outcomes are in the sample space? b. Assuming all of the outcomes in the samp
> Consider a multiple-choice test with a total of four possible options for each question. a. What is the probability of guessing correctly on one question? (Assume that there are three incorrect options and one correct option.) b. What is the probability
> a. On a true/false quiz in which you are guessing, what is the probability of guessing correctly on one question? b. What is the probability that a guess on one true/false question will be incorrect?
> Refer to exercise 5.11 for information about cards. If you draw one card randomly from a standard 52-card playing deck, what is the probability that it will be the following: a. A black card b. A diamond c. A face card (jack, queen, or king) d. A nine e.
> There are four suits: clubs ( ), diamonds ( ), hearts ( ), and spades ( ), and the following cards appear in each suit: ace, 2, 3, 4, 5, 6, 7, 8, 9, 10, jack, queen, king. The jack, queen, and king are called face cards because they have a drawing of a f
> For each of the values, state whether the number could be the probability of an event. Give a reason for your answers. a. 99% b. 0.9 c. 9.9 d. 0.0099 e. -0.90
> For each of the values, state whether the number could be the probability of an event. Give a reason for your answers. a. 0.26 b. -0.26 c. 2.6 d. 2.6% e. 26
> A recent Pew Research poll asked respondents to fill in the blank to this question: “The country ____ when it comes to giving equal rights to women” with one of three choices. The results are shown in the following t
> A person is selected randomly from the entire group whose responses are summarized in the table for exercise 5.41. We want to find the probability that the person selected is a male who said “hasn’t gone far enough.” a. Which of the following statements
> The scatterplot shows the median weekly earning (by quarter) for men and women in the United States for the years from 2005 through 2017. The correlation is 0.974. (Source: Bureau of Labor Statistics) a. Use the scatterplot to estimate the median weekly
> Find the frequency, proportion, and percentage of brown-haired people in Table 1A on page 31.
> The graph shows the heights of mothers and daughters. (Source: StatCrunch: Mother and Daughter Heights.xls. Owner: craig_slinkman) a. As the data are graphed, which is the independent variable and which the dependent variable? b. From the graph, approxi
> The following table shows the number of text messages sent and received by some people in one day. (Source: StatCrunch: Responses to survey how often do you text? Owner: Webster West. A subset was used.) a. Make a scatterplot of the data, and state the s
> The table shows the Earned Run Average (ERA) and WHIP rating (walks plus hits per inning) for the top 40 Major League Baseball pitchers in the 2017 season. Top pitchers will tend to have low ERA and WHIP ratings. (Source: ESPN.com) a. Make a scatterplot
> The following table give the Rotten Tomatoes and Metacritic scores for the several movies produced in 2017. Both of these ratings systems give movies a score using a scale from 0 to 100. (Source: vox.com) a. Use technology to make a scatterplot using Rot
> The following table gives the number of millionaires (in thousands) and the population (in hundreds of thousands) for the states in the northeastern region of the United States in 2008. The numbers of millionaires come from Forbes Magazine in March 2007.
> The following table gives the distance from Boston to each city and the cost of a train ticket from Boston to that city for a certain date. a. Use technology to produce a scatterplot. Based on your scatterplot do you think there is a strong linear relat
> The following table gives the distance from Boston to each city (in thousands of miles) and gives the time for one randomly chosen, commercial airplane to make that flight. Do a complete regression analysis that includes a scatterplot with the line, inte
> The graph shows the monthly premiums for a 10-year $250,000 male life insurance policy by age of purchase. For example, a 20-year-old male could purchase such a policy for about $10 per month, while a 50-year-old male would pay about $24 per month for th
> The following graph shows the average car insurance premium for a sample of ages. (Source: valuepenguin.com) a. Explain what the graph tells us about insurance rates for drivers at different ages. Explain why insurance rates might follow this trend. b. W
> Find the frequency, proportion, and percentage of women in Table 1A on page 31.
> The following figure shows a scatterplot with a regression line. The data are for the 50 states. The predictor is the percentage of adults who smoke. The response is the percentage of high school students who smoke. (The point in the lower left is Utah.)
> The following figure shows a scatterplot with the regression line. The data are for the 50 states. The predictor is the percentage of smoke free homes. The response is the percentage of high school students who smoke. The data came from the Centers for D
> Indicate which variable you think should be the predictor (x) and which variable should be the response (y). Explain your choices. a. A researcher measures subjects’ stress levels and blood pressures. b. Workers who commute by car record the length of th
> Indicate which variable you think should be the predictor (x) and which variable should be the response (y). Explain your choices. a. You have collected data on used cars for sale. The variables are price and odometer readings of the cars. b. Research is
> The figure shows a scatterplot of the height of the left seat of a seesaw and the height of the right seat of the same seesaw. Estimate the numerical value of the correlation, and explain the reason for your estimate.
> The following graph shows the winning percentages in singles matches and doubles matches for a sample of male professional tennis players. (Source: tennis.com) a. Based on this scatterplot, would you say there is a strong linear association between these
> The scatterplot shows a solid blue line for predicting weight from age of men; the dotted red line is for predicting weight from age of women. The data were collected from a large statistics class. a. Which line is higher and what does that mean? b. Whic
> The correlation between height and armspan in a sample of adult women was found to be r = 0.948. The correlation between arm span and height in a sample of adult men was found to be r = 0.868. Assuming both associations are linear, which association—the
> Measurements were made for a sample of adult men. Assume that the association between their hand length and foot length is linear. Output for predicting foot length from hand length is provided from several different statistical technologies. a. Report t
> Measurements were made for a sample of adult men. A regression line was fit to predict the men’s arm span from their height. The output from several different statistical technologies is provided. The scatterplot confirms that the assoc
> a. A hospital employs 346 nurses, and 35% of them are male. How many male nurses are there? b. An engineering firm employs 178 engineers, and 112 of them are male. What percentage of these engineers are female? c. A large law firm is made up of 65% male
> The computer output shown below is for predicting foot length from hand length (in centimeters) for a group of women. Assume the trend is linear. Summary statistics for the data are shown in the table below. a. Report the regression equation, using the
> TI-84 output from a linear model for predicting arm span (in centimeters) from height (in inches) is given in the figure. Summary statistics are also provided. To do parts a through c, assume that the association between arm span and height is linear.
> The scatterplot shows the size (in square feet) and selling prices for homes in a certain zip code in California. (Source: realtor.com) a. Use the graph to estimate the selling price of a home with 2000 square feet. b. Use the equation to predict the sel
> If there is a positive correlation between number of years studying math and shoe size (for children), does that prove that larger shoes cause more studying of math or vice versa? Can you think of a confounding variable that might be influencing both of
> Answer the questions using complete sentences. a. An economist noted the correlation between consumer confidence and monthly personal savings was negative. As consumer confidence increases, would we expect monthly personal savings to increase, decrease,
> What is an influential point? How should influential points be treated when doing a regression analysis? b. What is the coefficient of determination and what does it measure? c. What is extrapolation? Should extrapolation ever be used? Answer the questio
> Assume that in a sociology class, the teacher gives a midterm exam and a final exam. Assume that the association between midterm and final scores is linear. Here are the summary statistics: a. Find and report the equation of the regression line to predi
> Assume that in a political science class, the teacher gives a midterm exam and a final exam. Assume that the association between midterm and final scores is linear. The summary statistics have been simplified for clarity see Guidance on page 209. Accord
> The following table shows the average SAT Math and Critical Reading scores for students in a sample of states. A scatterplot for these two variables suggests a linear trend. (Source: qsleap.com) a. Find and report the value for the correlation coefficie
> Data from the National Data shown in the table are the 4th-grade reading and math scores for a sample of states from the National Assessment of Educational Progress. The scores represent the percentage of 4thgraders in each state who scored at or above b
> Suppose you wanted to know whether living situation was associated with number of units the student had acquired. Could you do that with this data table? If so, which variables would you use?
> Data on the 3-point percentage, field-goal percentage, and free-throw percentage for a sample of 50 professional basketball players were obtained. Regression analyses were conducted on the relationships between 3-point percentage and field-goal percentag
> Data on the number of home runs, strikeouts, and batting averages for a sample of 50 Major League Baseball players were obtained. Regression analyses were conducted on the relationships between home runs and strikeouts and between home runs and batting a
> Data were collected that included information on the weight of the trash (in pounds) on the street for one week and the number of people who live in the house. The following figure shows a scatterplot with the regression line. a. Is the trend positive or
> Grades on a political science test and the number of hours of paid work in the week before the test were recorded. The instructor was trying to predict the grade on a test from the hours of work. The following figure shows a scatterplot and the regressio
> The scatterplot shows the average teacher pay and high school graduation percentage rate for each of the 50 states and the District of Columbia. The regression equation is also shown. (Source: 2017 World Almanac Book of Facts and higheredinfo.org) a. Ba
> The scatterplot shows the average teacher pay and the per pupil expenditure for each of the 50 states and the District of Columbia. The regression equation is also shown. (Source: The 2017 World Almanac and Book of Facts). a. From the scatterplot is the
> The table shows the calories in a five-ounce serving and the % alcohol content for a sample of wines. (Source: healthalicious.com) a. Make a scatterplot using % alcohol as the independent variable and calories as the dependent variable. Include the regr
> The following table shows the weights and prices of some turkeys at different supermarkets. a. Make a scatterplot with weight on the x-axis and cost on the y-axis. Include the regression line on your scatterplot. b. Find the numerical value for the corre
> The following figure shows the relationship between the number of miles per gallon on the highway and that in the city for some cars. a. Report the slope and explain what it means. b. Either interpret the intercept (7.792) or explain why it is not approp
> The equation for the regression line relating the salary and the year first employed is given above the figure. a. Report the slope and explain what it means. b. Either interpret the intercept (4,255,000) or explain why it is not appropriate to interpret
> Suppose a surfer wanted to learn if surfing during a certain time of day made one less likely to be attacked by a shark. Using the Shark Attacks Worldwide data set, which variables could the surfer use in order to answer this question?
> Suppose a doctor telephones those patients who are in the highest 10% with regard to their recently recorded blood pressure and asks them to return for a clinical review. When she retakes their blood pressures, will those new blood pressures, as a group
> Some investors use a technique called the “Dogs of the Dow” to invest. They pick several stocks that are performing poorly from the Dow Jones group (which is a composite of 30 well known stocks) and invest in these. Explain why these stocks will probably
> Does a correlation of -0.70 or +0.50 give a larger coefficient of determination? We say that the linear relationship that has the larger coefficient of determination is more strongly correlated. Which of the values shows a stronger correlation?
> If the correlation between height and weight of a large group of people is 0.67, find the coefficient of determination (as a percentage) and explain what it means. Assume that height is the predictor and weight is the response, and assume that the associ
> Suppose that the growth rate of children looks like a straight line if the height of a child is observed at the ages of 24 months, 28 months, 32 months, and 36 months. If you use the regression obtained from these ages and predict the height of the child
> The scatterplot shows the LSAT (Law School Aptitude Test) scores for a sample of law schools and the percent of students who were employed immediately after law school graduation. Do you think the correlation coefficient among these variables is positive
> The figure shows a scatterplot of birthrate (live births per 1000 women) and the age of the mother in the United States. Would it make sense to find the correlation for this data set? Explain. According to this graph, at approximately what age does the h
> The first scatterplot shows the college tuition and percentage acceptance at some colleges in Massachusetts. Would it make sense to find the correlation using this data set? Why or why not? b. The second scatterplot shows the composite grade on the ACT
> United Press International published an article with the headline “Study Finds Correlation between Educations, Life Expectancy.” Would you expect this correlation to be negative or positive? Explain your reasoning in the context of this headline.