Question: The Toy Association tracks sales of toys

> For the following experiment, indicate whether it was single-blind, double-blind, or not blinded at all. Explain your reasoning. Does a “stop smoking” program work better if it costs more? Smokers responding to an advertisement offering to help them stop

> A study finds that during blizzards, online sales are highly associated with the number of snow plows on the road; the more plows, the more online purchases. The director of an association of online merchants suggests that the organization should encoura

> A larger firm is considering acquiring the bookstore of Exercise 1. An analyst for the firm, noting the relationship seen in Exercise 1, suggests that when they acquire the store they should hire more people because that will drive higher sales. Is his c

> If we assume that the conditions for correlation are met, which of the following are true? If false, explain briefly. a) A correlation of 0.02 indicates a strong positive association. b) Standardizing the variables will make the correlation 0. c) Addi

> If we assume that the conditions for correlation are met, which of the following are true? If false, explain briefly. a) A correlation of -0.98 indicates a strong, negative association. b) Multiplying every value of x by 2 will double the correlation.

> A company that relies on Internet-based advertising linked to key search terms wants to understand the relationship between the amount it spends on this advertising and revenue (in $). a) Which variable is the explanatory or predictor variable? b) Whic

> The human resources department at a large multinational corporation wants to be able to predict average salary for a given number of years’ experience. Data on salary (in $1000s) and years of experience were collected for a sample of employees. a) Which

> Disk drives have been getting larger. Their capacity is now often given in terabytes (TB) where 1 TB = 1000 gigabytes, or about a trillion bytes. A search of prices for external disk drives on Amazon.com in mid-2016 found the following data: (Data in Dis

> An online investment blogger advises investing in mutual funds that have performed badly the past year because “regression to the mean tells us that they will do well next year.” Is he correct?

> A CEO complains that the winners of his “rookie junior executive of the year” award often turn out to have less impressive performance the following year. He wonders whether the award actually encourages them to slack off. Can you offer a better explanat

> For the disk drives in Exercise 2, we want to predict Price from Capacity. a) Find the slope estimate, b1 and interpret it in words. b) Does the slope seem reasonable? Explain. c) Find the intercept, b0. d) What does it mean, in this context? Is it meani

> For the following experiment, indicate whether it was single-blind, double-blind, or not blinded at all. Explain your reasoning. Makers of a new frozen entrée arranged for it to be served to randomly selected customers at a restaurant in place of the equ

> For the bookstore of Exercise 1, the manager wants to predict Sales from Number of Sales People Working. a) Find the slope estimate, b1. b) What does it mean, in this context? c) Find the intercept, b0. d) What does it mean, in this context? Is it meanin

> For the hard drive data in Exercise 2, the correlation is 0.988 and other summary statistics are: a) If a drive has a capacity of 17.46 TB (or 1 SD above the mean), how many standard deviations above or below the mean price of $785.82 do you expect the

> For the bookstore sales data in Exercise 1, the correlation of number of sales people and sales is 0.965. a) If the number of people working is 2 standard deviations above the mean, how many standard deviations above or below the mean do you expect sales

> True or False. If False, explain briefly. a) Some of the residuals from a least squares linear model will be positive and some will be negative. b) Least Squares means that some of the squares of the residuals are minimized. c) We write y^ to denote the

> Consider the following data from a small bookstore. a) Prepare a scatterplot of Sales against Number of Sales People Working. b) What can you say about the direction of the association? c) What can you say about the form of the relationship? d) What ca

> The histogram shows the December charges (in $) for 5000 customers from one marketing segment from a credit card company. (Negative values indicate customers who received more credits than charges during the month.) a) Write a short description of this d

> For the data in Exercise 2: a) Find the quartiles using your calculator. b) Find the quartiles using the Tukey method (page 65). c) Find the IQR using the quartiles from part b. d) Find the standard deviation. Exercise 2: As the new manager of a small c

> For the data in Exercise 1: a) Find the quartiles using your calculator. b) Find the quartiles using the Tukey method (page 65). c) Find the IQR using the quartiles from part b. d) Find the standard deviation.

> Jeff, a sales manager of a car dealership, believes that his sales force sells a car to 35% of the customers who stop by the showroom. He needs the dealership to make 50 sales this month to get a special bonus of $100,000. Approximately 120 customers vis

> Suppose the archer from Exercise 58 shoots 10 arrows. a) Find the mean and standard deviation of the number of bull’s-eyes she may get. b) What’s the probability that she never misses? c) What’s the probability that there are no more than 8 bull’s-eyes?

> Analysts from the Internet company of Exercise 5 are now concerned that customers who come directly to their site (by typing their URL into a browser) might respond differently than those referred to the site from other sites (such as search engines). Th

> Suppose we choose 12 people instead of the 5 chosen in Exercise 57. a) Find the mean and standard deviation of the number of right-handers in the group. b) What’s the probability that they’re not all right-handed? c) What’s the probability that there

> Consider our archer from Exercise 52. a) How many bull’s-eyes do you expect her to get? b) With what standard deviation? c) If she keeps shooting arrows until she hits the bull’s-eye, how long do you expect it will take?

> Consider our group of 5 people from Exercise 51. a) How many lefties do you expect? b) With what standard deviation? c) If we keep picking people until we find a lefty, how long do you expect it will take?

> The manufacturer in Exercise 54 has noticed that the number of faulty cell phones in a production run of cell phones is usually small and that the quality of one day’s run seems to have no bearing on the next day. a) What model might you use to model th

> A website manager has noticed that during the evening hours, about 3 people per minute check out from their shopping cart and make an online purchase. She believes that each purchase is independent of the others and wants to model the number of purchases

> The scatterplot shows, for 2015 cars, the carbon footprint (tons of CO2 per mile) vs. the new Environmental Protection Agency (EPA) highway mileage for 69 family sedans as reported by the U.S. government (www.fueleconomy.gov/feg/byclass.htm); the cars in

> At a small company, the head of human resources wants to examine salary to prepare annual reviews. He selects 28 employees at random with job types ranging from 01 = Stocking clerk to 99 = President. He plots Salary ($) against Job Type and finds a stron

> A sales manager for a major pharmaceutical company analyzes last year’s sales data for her 96 sales representatives, grouping them by region (1 = East Coast United States; 2 = Mid West United States; 3 = West United States; 4 = South Un

> Insurance companies carefully track claims histories so that they can assess risk and set rates appropriately. The National Insurance Crime Bureau reports that Honda Accords, Honda Civics, and Toyota Camrys are the cars most frequently reported stolen, w

> A CEO announces at the annual shareholders meeting that the new see-through packaging for the company’s flagship product has been a success. In fact, he says, “There is a strong correlation between packaging and sales.” Criticize this statement on statis

> In an effort to check the quality of their cell phones, a manufacturing manager decides to take a random sample of 10 cell phones from yesterday’s production run, which produced cell phones with serial numbers ranging (according to when they were produce

> The 30 quarterbacks in Exercise 32 had an average Salary of $13,788,022 1SD = $8,130,5362. The correlation between Salary and Total QBR = 0.278. If a player had a Total QBR rating 1 SD below the average, what Salary would you predict for it? Exercise 32

> For the data in Exercise 31, the average Sales was 52,697 pounds (SD = 10,261 pounds), and the correlation between Price and Sales was = -0.547. If the Price in a particular week was one SD higher than the mean Price, how much pizza would you predict was

> In 2016, the Los Angeles Dodgers spent nearly one quarter billion (!) dollars on salaries for their players (Spotrac). Is there a relationship between salary and team performance in Major League Baseball? For the 2016 season, a linear model fit to the nu

> Is there a relationship between total team salary and the performance of teams in the National Football League (NFL)? For the 2016–2017 season, a linear model predicting Wins (out of 16 regular season games) from the total team Salary ($M) for the 32 tea

> Quarterback performance 2017. The average salary for 30 top NFL quarterbacks in 2017 was just over $13,000,000. A linear model to predict Salary from Total QBR (an overall measure of performance based on game statistics) found the following: a) What i

> A linear model fit to predict weekly Sales of frozen pizza (in pounds) from the average Price ($/unit) charged by a sample of stores in the city of Dallas in 39 recent weeks is: (Data in Pizza prices) a) What is the explanatory variable? b) What is t

> Here are several scatterplots. The calculated correlations are -0.977, -0.021, 0.736, and 0.951. Which is which? (a) (b) (c) (d)

> Here are several scatterplots. The calculated correlations are -0.923, -0.487, 0.006, and 0.777. Which is which? (a) (b) (c) (d)

> Owners of a new coffee shop tracked sales for the first 20 days and displayed the data in a scatterplot a) Make a histogram of the daily sales since the shop has been in business. b) State one fact that is obvious from the scatterplot, but not from the

> A ceramics factory can fire eight large batches of pottery a day. Sometimes a few of the pieces break in the process. In order to understand the problem better, the factory records the number of broken pieces in each batch for three days and then creates

> A cable provider wants to contact customers in a particular telephone exchange to see how satisfied they are with the new digital TV service the company has provided. All numbers are in the 452 exchange, so there are 10,000 possible numbers from 452-0000

> Which of the scatterplots show: a) Little or no association? b) A negative association? c) A linear association? d) A moderately strong association? e) A very strong association? (1) [:.. (3) (4)

> Which of the scatterplots show: a) Little or no association? b) A negative association? c) A linear association? d) A moderately strong association? e) A very strong association? (1) (3) (4)

> Suppose you were to collect data for each pair of variables. You want to make a scatterplot. Which variable would you use as the explanatory variable and which as the response variable? Why? What would you expect to see in the scatterplot? Discuss the li

> Suppose you were to collect data for each pair of variables. You want to make a scatterplot. Which variable would you use as the explanatory variable and which as the response variable? Why? What would you expect to see in the scatterplot? Discuss the li

> In 2014, Pew Research Center released the results of a survey among U.S. adults that asked nearly 2000 people how satisfied they are with their current financial situation (www.pewsocialtrends .org/datasets/). Responses were collected by gender, using a

> An insurance company is updating its payouts and cost structure for their insurance policies. Of particular interest to them is the risk analysis for customers currently on heart or blood pressure medication. The Centers for Disease Control and Preventio

> Here’s a pie chart of the data in Exercise 16. a) Which display of these data is best for comparing the market value of these brands? Explain. b) Does Pepsi or Red Bull have a larger market value? Is that comparison easier to make wit

> Here’s a bar chart of the data in Exercise 15. a) Compared to the pie chart in Exercise 15, which is better for displaying the relative portions of market share? Explain. b) What is missing from this display that might make it somewha

> An Olympic archer is able to hit the bull’seye 80% of the time. Assume each shot is independent of the others. If she shoots 6 arrows, what’s the probability of each of the following results? a) Her first bull’s-eye comes on the third arrow. b) She mis

> Tuition 2016. In 2016, the mean tuition of private colleges and universities was $18,230, with a standard deviation of $7272. The mean tuition for public colleges and universities was $9624, with a standard deviation of $4669. The distribution of tuition

> The 1057 houses described in Exercise 44 have a mean price of $167,900, with a standard deviation of $77,158. The mean living area is 1819 sq. ft., with a standard deviation of 663 sq. ft. Which is more unusual, a house in that market that sells for $400

> A second report by the National Center for Productivity analyzed the relationship between productivity and wages. They used the graph from Exercise 67, with the x-axis labeled “wages.” Comment on any problems you see with their analysis.

> The National Center for Productivity releases information on the efficiency of workers. In a recent report, they included the following graph showing a rapid rise in productivity. What questions do you have about this? 3.5 2.5 Productivity

> The claims about climate change suggest two possible effects: more storms and bigger, stronger storms. Here are plots similar to those of Exercise 65, but for major hurricanes. (Data in Hurricane history) a) Describe the distribution. Here is the time

> The North Atlantic hurricane database, or HURDAT, is a database of all tropical storms and hurricanes for the Atlantic Ocean, Gulf of Mexico, and Caribbean Sea, reporting numbers of storms each year since 1850. The older portion of the database reflects

> Holes-R-Us, an Internet company that sells piercing jewelry, keeps transaction records on its sales. At a recent sales meeting, one of the staff presented the following histogram and summary statistics of the ZIP codes of the last 500 customers, so that

> Each house listed on the multiple listing service (MLS) is assigned a sequential ID number. A recently hired real estate agent decided to examine the MLS numbers in a recent random sample of homes for sale by one real estate agency in nearby towns. To be

> The discounts negotiated by the car buyers in Exercise 32 are classified by whether the buyer was Male 1code = 02 or Female 1code = 12. Compare the discounts of men vs. women using an appropriate display and write a brief summary of the differences.

> The 70 mutual funds of Exercise 31 are classified into four types: U.S. Domestic Equity Funds, Bond Funds, International Funds, and Other Funds. Compare the 12 month returns of the four types of funds using an appropriate display and write a brief summar

> A manufacturer of game controllers is concerned that their controller may be difficult for left-handed users. They set out to find lefties to test. About 13% of the population is left-handed. If they select a sample of five customers at random in their s

> For each CEO, a code is listed that corresponds to the industry of the CEO’s company. Here are a few of the codes and the industries to which they correspond: A recently hired investment analyst has been assigned to examine the indust

> A philanthropic organization has a database of millions of donors that they contact by mail to raise money for charities. One of the variables in the database, Title, contains the title of the person or persons printed on the address label. The most comm

> A real estate agent notices that houses with fireplaces often fetch a premium in the market and wants to assess the difference in sales price of 60 homes that recently sold. The data and summary are shown in the table. Write a report summarizing the fi

> Engineers at a computer production plant tested two methods for accuracy in drilling holes into a PC board. They tested how fast they could set the drilling machine by running 10 boards at each of two different speeds. To assess the results, they measure

> Look again at the histograms of test scores for the three statistics classes in Exercise 55. a) Overall, which class do you think performed better on the test? Why? b) How would you describe the shape of each distribution? c) Match each class with the co

> Three statistics classes all took the same test. Here are histograms of the scores for each class. a) Which class had the highest mean score? b) Which class had the highest median score? c) For which class are the mean and median most different? Which

> Here is an ogive of the distribution of monthly returns for a group of aggressive (or high growth) mutual funds over a period of 25 years. (Recall from Exercise 53 that an ogive, or cumulative relative frequency graph, shows the percent of cases at or be

> How fast do horses run? Kentucky Derby winners top 30 mph, as shown in the graph. This graph shows the percentage of Kentucky Derby winners that have run slower than a given speed. Note that few have won running less than 33 mph, but about 95% of the win

> Historic ozone levels (in parts per billion, ppb) were recorded at sites in New Jersey monthly. Here are boxplots of the data for each month (over 46 years) lined up in order ( January = 1). a) In what month was the highest ozone level ever recorded? b

> The boxplots display bottle prices (in dollars) of dry Riesling wines produced by vineyards along three of the Finger Lakes in upstate New York. a) Which lake region produced the most expensive wine? b) Which lake region produced the cheapest wine? c)

> During the 18 years from 2000 through 2017, there were 128 major hurricanes in the Atlantic basin. Assume that hurricanes are independent and the mean has not changed. a) What is the mean number of major hurricanes per year? b) What is the standard dev

> An Internet sale site randomly sent customers to one of three versions of its welcome page. It recorded how long each visitor stayed in the site. Here is a diagram of that experiment. Fill in the parts of the experiment.

> American automobile companies are becoming more motivated to improve the fuel efficiency of the automobiles they produce. It is well known that fuel efficiency is impacted by many characteristics of the car. Describe what these boxplots tell you about th

> A driver has recorded and posted on the Internet (www.randomuseless.info/gasprice/gasprice.html) the price he paid for gasoline at every purchase from 1979 to 2012. Since 1984 all purchases were self-serve and all were for premium (92–9

> The data set provided contains 2016 (4th quarter) unemployment rates for 38 developed countries (www.oecd.org). Produce an appropriate graphical display and brief ly describe the distribution of unemployment rates. Report and comment on any outliers you

> In the early days of the iPod, MacInTouch (www.macintouch.com/reliability/ipodfailures.html) surveyed readers about reliability. Of the 8926 iPods owned at that time, 7510 were problem-free while the other 1416 failed. From the data, compute the failure

> Insurance companies don’t know whether a policy they’ve written is profitable until the policy matures (expires). To see how they’ve performed recently, an analyst looked at mature policies and investigated the net profit to the company (in $). a) Make

> Sales (in $) for one week were collected for 18 stores in a food store chain in the northeastern United States. The stores and the towns they are located in vary in size. a) Make a suitable display of the sales from the data provided. b) Summarize the ce

> A real estate agent has surveyed houses in 20 nearby ZIP codes in an attempt to put together a comparison for a new property that she would like to put on the market. She knows that the size of the living area of a house is a strong factor in the price,

> A startup company is planning to build a new golf course. For marketing purposes, the company would like to be able to advertise the new course as one of the more difficult courses in the state of Vermont. One measure of the difficulty of a golf course i

> Established in Paris in 1961, the Organization for Economic Cooperation and Development (OECD) (www.oecd.org) collects information on many economic and social aspects of countries around the world. Here are the 2016 GDP growth rates (in percentages) of 3

> The U.S. Energy Information Administration (EIA) collects data on the total energy used per capita in transportation for each state and the District of Columbia. The data show the per capita consumption in the year 2015 in millions of BTU per person. Wri

> An insurance company needs to assess the risks associated with providing hurricane insurance. During the 18 years from 2000 to 2017, Florida has been affected by 29 hurricanes. If hurricanes are independent and the mean has not changed, what is the proba

> The weekly prices of one brand of frozen pizza over a three-year period in Chicago are provided in the data file. Use the price data to answer the following questions. a) Find the five-number summary for these data. b) Find the range and IQR for these da

> The weekly prices of one brand of frozen pizza over a three-year period in Dallas are provided in the data file. Use the price data to answer the following questions. a) Find the five-number summary for these data. b) Find the range and IQR for these dat

> Look once more at data of home runs hit by Mark McGwire during his 16-year career as seen in Exercise 36. a) Would you use the mean or the median to summarize the center of this distribution? Why? b) Find the median. c) Without actually finding the mean,

> Look once more at data of hockey games played each season by Wayne Gretzky, seen in Exercise 35. a) Would you use the mean or the median to summarize the center of this distribution? Why? b) Without actually finding the mean, would you expect it to be lo

> McGwire. In his 16-year career as a player in major league baseball, Mark McGwire hit 583 home runs, placing him eighth on the all-time home run list (as of 2008). Here are the number of home runs that McGwire hit for each year from 1986 through 2001: 3,

> During his 20 seasons in the National Hockey League, Wayne Gretzky scored 50% more points than anyone else who ever played professional hockey. He accomplished this amazing feat while playing in 280 fewer games than Gordie Howe, the previous record holde

> Use the data set of Exercise 32 to answer the following questions. a) Find the five-number summary for these data. b) Create a boxplot for these data. c) What can you see, if anything, in the histogram of Exercise 32 that isn’t clear in

> Use the data set of Exercise 31 to answer the following questions. a) Find the five-number summary for these data. b) Find appropriate measures of center and spread for these data. c) Create a boxplot for these data. d) What can you see, if anything, in

> A researcher, interested in studying gender differences in negotiations, collects data on the prices that men and women pay for new cars. Here is a histogram of the discounts (the amount in $ below the list price) that men and women received at one car d

> On December 30, 2016, the Standard and Poor’s (S&P) 500 index hit an all-time high. During 2016, the S&P returned 12.25%. Here is a histogram of the 2016 net returns (total return – annual expenses) for Money M

> Cellophane that is going to be formed into bags for items such as dried beans or bird seed is passed over a light sensor to test if the alignment is correct before it passes through the heating units that seal the edges. Small adjustments can be made by

> The website LosAngelesGasPrices.com has current gasoline prices all over the United States. In the week of September 10, 2017, the following histogram shows the gas prices at 44 stations in the San Francisco Bay Area. Describe the shape of this distribut