- Access the monthly percentage of 311 calls attended within 60 seconds from April 2007 to November 2016 in San Francisco (“311_Call_Metrics_by_Month”). Construct a line chart and discuss whether
- The file “canadaemplmntdata” contains quarterly Canada employment data for multiple job sectors. The variable name is VALUE, and it is measured in thousands. With computer software assistance,
- Returning to the data set “canadaemplmntdata” from Problem 17.4, get a line chart of Accommodation jobs by subsetting by VECTOR = v81682.Problem 17.4The file “canadaemplmntdata” contains
- Monthly amount of recycled water (acre feet) delivered in the city of Los Angeles is available (“Recycled_Water_LA”).a) Use Minitab to build a line chart. Does there appear to be a trend?
- The table below shows the most recent observations of quarterly wine production (in pounds) from a California winery.a) According to the naive method, what is the forecast for Q4-18?b) According to
- A firm that manufactures snowboards records monthly sales. They have data until August 2018, when sales were $109 303.a) According to the naive method, what is the forecast for September 2018?b)
- Consider annual corporate taxes reported by the California Franchise Tax Board from 1950 to 2015 (file “Ca_Income_Loss_Tax_Assessed”; variable Tax Assessed on Net Income.).a) Using statistical
- The file from Problem 17.10 also includes the variable Returns w/Net Income. With the help of statistical software, create a simple exponential smoothing chart.Problem 17.10Consider annual corporate
- Returning to Problem 17.2,a) Using Minitab, fit a linear trend model.b) Using Minitab, fit a quadratic trend model.c) Visually, which of the two fits appears to be best?Problem 17.2Access the monthly
- Figure 17.2 indicates a trend in monthly auto imports reported by Maryland Port Administration. Using the variable Import Auto Units in the file “Maryland_Port_Cargo,” forecast imports three
- Subset the Buffalo, New York, curb recycling data (“Buffalo_Monthly_ Recycling”), by the variable Type = “Curb Recycling,” with the help of computer software to fit aa) Linear trend model.b)
- Download the file “Buffalo_Monthly_Recycling.” For the variable Type = “Curb Garbage,”a) Construct a line chart and interpret.b) Fit the data using the double exponential smoothing method.
- Returning to the data from Problem 17.6, according to the seasonal naive method, what is the forecast for Q4-18?Problem 17.6The table below shows the most recent observations of quarterly wine
- Returning to the data from Problem 17.6, according to the seasonal naive method, what is the forecast for Q1-19?Problem 17.6The table below shows the most recent observations of quarterly wine
- Using the variable Export Auto Units in the file “Maryland_Port_ Cargo,”a) Construct a line chart and argue why a quadratic trend would be reasonable.b) Fit the data using the quadratic trend
- The file “canadaemplmntdata” contains quarterly Canada employment data for multiple job sectors. The variable name is VALUE, and it is measured in thousands. With computer software assistance,
- Returning to the data set “canadaemplmntdata” from Problem 17.19, fit a Holt–Winters model for Accommodation jobs after subsetting by VECTOR = v81682.Problem 17.19The file
- Often, it is not enough to assume that seasonality or trend components are present. We must evaluate the need to fit these components. The file “canadaemplmntdata” contains quarterly Canada
- Returning to the data set “canadaemplmntdata” from Problem 17.21,a) Construct a line chart for seasonally unadjusted tourism employment data by subsetting the data by VECTOR = v81675.b) Construct
- Another easy way to assess trend or seasonality fits are to plot the residuals, the detrended or deseasonalized data. Consider annual returns with net income reported by the California Franchise Tax
- Consider annual corporate taxes (file “Ca_Income_Loss_Tax_Assessed”; variable Tax Assessed on Net Income.).a) Fit a Holt–Winters model and record the model residuals.b) Construct line charts of
- Consider the data in the file “Ca_Income_Loss_Tax_Assessed”; variable Returns w/Net Income.a) Using statistical software, create a double exponential smoothing chart.b) How would you argue that
- Subset the Buffalo, New York, recycled tires data (“Buffalo_Monthly_ Recycling”), by the variable Type = “Recycled Tires.” With the help of statistical software to fit a,a) Simple exponential
- Subset the Buffalo New York recycled tires data (“Buffalo_Monthly_ Recycling”), by the variable Type = “E-waste” and exclude data before April 30, 2012.With the help of statistical software
- The variable name VALUE in the file (“canadaemplmntdata”) provides quarterly Canada employment data (in thousands).With statistical software assistance,a) Fit a Holt–Winters model after
- Returning to the data set “canadaemplmntdata” from Problem 17.30, for other industries jobs (subsetting by VECTOR = v81687),a) Fit a Holt–Winters model.b) Fit a simple exponential model.Problem
- The Denver Colorado marijuana gross sales data file, “CO_mj_gross_ sales,” includes monthly retail total gross sales.a) Fit a Holt–Winters model.b) Fit a double exponential model.
- Every year, administrators of the San Francisco airport conduct a survey to analyze guest satisfaction. Suppose management wants to compare the restaurant quality scores for four terminals.
- A study is proposed to evaluate three systems to reduce stress among police officers. Police officers are randomly assigned to each system, and a stress score is calculated from a questionnaire.a)
- State what are the required assumptions to implement ANOVA.
- Using data from 55 communities in Baltimore on affordability index for mortgages (affordm15), and for rent (affordr15), a regression model was constructed to fit affordm15 based on affordr15. Below
- A sample of 25 observations gave a sample mean of 32.6 and a sample variance of 5.11. What is the TSS?
- Using Eq. (13.1), show that Eq. (13.2) holds. Y = B₁ + B₁X + € (13.1)
- State what are the main assumptions required to implement one-factor ANOVA.
- Using Eq. (13.1), show that Var(Y) = σ2. Y = B₁ + B₁X + € (13.1)
- According to simple linear regression notation, explain what is the difference between Y and Ŷ.
- In an effort to determine if advertisement expenditures lead to greater revenue from online sales of surfboards, a firm examined 32 weeks of data. The regression model was Y = revenue (in thousand of
- At the admissions office of a university, they have been using past data to study how high school GPA (HSgpa) and combined math and critical reading SAT scores (SAT) are associated to college
- Technically, in the simple linear regression method, Y|X = x ∼ N(β0 + β1 x, σ). If β0 = 11.45 and β1 = −3.21, what would be the expected value of Y given X = 1.79?
- Download the file “gasConsumption_deliverytrucks.”a) Use statistical software to get the regression equation (14.1).b) Construct a scatterplot of gas consumption and weight of the cargo, cargo
- Some years ago, NBC News published an article titled “Praise the Lard? Religion Linked to Obesity in Young Adults.” It revealed how a study found that young adults that attended religious
- Refer to the ANOVA table below.a) How many predictors were tested?b) Write the null and alternative hypothesis.c) Is the null rejected at 5% significance?
- At the admissions office of a university, past data has been used to study how high school GPA (HSgpa) and combined math and critical reading SAT scores (SAT) are associated to college freshmen GPA
- In an effort to determine if advertisement expenditures lead to greater revenue from online sales of surfboards, a firm considers 32 weeks of data. The regression model was Y = revenue (in thousand
- Universities use indexes to measure the eligibility of admission candidates. These indexes vary, but they are generally a function of SAT scores and GPA. For University Free for All (UFfA), the
- Download the file “gasConsumption_deliverytrucks.”a) Perform an F-test at 5% significance on a regression model for gas consumption when cargoweight, delivery, and miles are the predictors.b) Do
- The table that follows presents R2 and R2a (percent) values for models with between five and eight predictors.a) What are the respective R2 and R2a values for the model with 8 predictors?b) What are
- Using 30 observations and 15 predictors, a firm has fit a multiple regression model for the salary of managers. Explain why inference is not reliable in this situation.
- In a move to make more data-driven decisions, the CEO of a technology company aims to build a regression model for customer experience using 25 predictors. Why should the company use a data set of at
- An organization wishes to build a model that estimates a ZIP Codes median home value based on median household income, unemployment, and median rent. Using the “2014_Housing_Market_Analysis_
- The table below is analogous to Table 14.4, but the predictors have been centered: X1 = centered PCNT_B_POV, X1 = centered NO_HS.a) Interpret the intercept.b) How have the coefficient estimates of
- Download the file “gasConsumption_deliverytrucks.”a) Construct a scatterplot matrix of gas, cargoweight, delivery, and miles and recall that the last three are the predictors. Do the predictors
- With the data set “Census_Data_Selected_socioeconomic_indicators_in_Chicago_2008_2012,” use statistical software to show that the coefficients, their standard errors, and t-tests are the ones
- Download the file “gasConsumption_deliverytrucks.”a) Create the new predictor m10 = miles∕10.b) Fit a regression model to predict gas consumption using delivery,m10, and cargoweight.c) Compare
- Download the file “Sustainability__2010-2013_Baltimore”; which has Baltimore data. We will model clogged13 (2013 rate of clogged storm drain reports per 1000 residents) considering clogged12,
- A model to predict prison sentence (in years) for men included the predictors: type of crime (criminal damage, burglary, robbery, drugs, public order, sexual, motoring, possession of weapon, and
- In an attempt to improve their current text translator, a company will assess three statistical approaches in translating three languages into English: Spanish, French, and Mandarin. Let Y = English
- State what are the four main assumptions required for inference during multiple linear regression analysis.
- The following regression model is fit to data Ŷ = 103.32 + 3.25X1 − 153.63X2 − 27.44X3. Why can’t we say that X2 is definitely the predictor with the strongest linear association with Y?
- Does use of ride sharing companies (e.g.Uber, Lyft) depend on gender? To answer this question, 799 responses to the San Francisco Travel Decision Survey were used. Below is a screenshot of Minitab
- A company classifies quality of the furniture it manufactures based on four categories: Excellent, Good, Acceptable, and Unacceptable. The quality department wants to test if quality rating is
- There is an excellent open data portal for the City of Edmonton, Canada. One data set comes from a survey to gather community insight, including residents, opinion about drones. Two drone aspects
- With the help of a computer, use NASA’s “Meteorite_Landings” to run a Wilcoxon signed-rank test at 5% significance to determine if the median mass of Pallasite meteorites is equal to 100 g. Why
- As part of a marketing study of beer X, 10 bars of similar size are chosen across the United States. The sales for each bar are recorded for the week before the ad campaign, and the week immediately
- With the help of a computer, use NASA’s “Meteorite_Landings” to run a sign test at 5% significance to determine if the median mass of Pallasite meteorites is equal to 100 g.
- Every year, administrators of the San Francisco airport conduct a survey to analyze guest satisfaction. Suppose management wants to compare the restaurant quality scores of four terminals. Restaurant
- Are drone owners in Edmonton, Canada, less concerned than people who do not own a drone about safety with drones flying over people? In a survey to gather community insight about drones, participants
- With the help of Minitab, and using the data set “2011_SFO_Customer_Survey,” first subset the rows by whether respondents made a restaurant purchase (“Q4C” = 1). Second, exclude rows where
- Is concern about safety with drones, flying over people, related to age? A survey was conducted in Edmonton, Canada, to gather community insight about drones. Participants provided feedback on “I
- Returning to Problem 11.35, if the difference is defined as superhero violent events per hour minus villain violent events per hour, use the Minitab output below to answer the following questions at
- Enrollment data of schools in Connecticut for the 2013–2014 school year are available in the file “School_Enrollment_Connecticut.” Note that the last row is for all of Connecticut and thus must
- From the file “Baltimore_Arts” get the number of art-related businesses per 1000 residents for Baltimore in 2011 and 2012 (artbus11 and artbus12 respectively).a) Perform a paired t-test at 5%
- Download Baltimore education data: “BaltimoreEducation_and_Youth__2010-2012_”a) Perform a two mean test at 5% significance to determine if the expected proportion of students receiving free or
- An analyst at the firm you work in was comparing the proportions from two independent samples. He was able to use a normal approximation and build a confidence interval for each proportion. Since
- Who is more violent, superheroes or villains? A CNN article reported on a research presentation on the matter. The research considered (a random sample) of 10 movies and evaluated the number of
- A professor has two possible routes to get to work from home. The distances are not the same but for her it is all about getting to work faster. She has tried both routes, but finds it hard to tell
- Inference is needed on the difference between the mean math SAT score of high school students who went to a 10-minute presentation (μ1, group A) and the mean math SAT score of high school students
- Have you ever wondered if the proportion of high school students that smoked cigarettes in the past 30 days is different for Hispanics and Whites? Perform a hypothesis test to check if this was the
- Ten people participated in a taste experiment to determine if there is a difference in the mean score of two cereals (where 100 is best).a) Write the null and alternative hypothesis.b) What is the
- You work for an insurance firm and you must choose between two companies to handle your employer’s investment portfolio. Although both companies have claims about the mean 1-year return for a $10
- A company’s data analyst performed a two sample t-test to compare the mean time to pack some jewelry using two separate machines. Curious, a manager asks the analyst if he used an equal variance
- A new machine was purchased to can tuna. With the old machine, a random sample of 16 cans revealed an average weight of 6.83 oz and a standard deviation of 0.64 oz. In an independent random sample
- Enrollment data of schools in Connecticut for the 2013–2014 school year are available in the file “School_Enrollment_Connecticut” α = 0.10. Note that the last row is for all of Connecticut and
- A realtor wants to compare asking prices per square foot for land in neighborhood 1 and neighborhood 2. He takes a random sample of 16 listings from neighborhood 1. From neighborhood 2, a random
- In the 2016 General Social Survey, one question was “What is the ideal number of children for a family to have?” Of the 738 men who answered, the mean response was 2.52 with a standard deviation
- For a new car model from Company M, engineers proposed a slight tweak in the engine design that could lead to better fuel efficiency. To test this, 10 cars were randomly assigned the originally
- If H0 ∶ μ1 − μ2 ≤ 0; H1 ∶ μ1 − μ2 > 0, which of the following is an equivalent statement? (More than one choice is possible.)a) H0 ∶ μ1 − μ2 < 0; H1 ∶ μ1 − μ2 ≥ 0b)
- If H0 ∶ μ1 − μ2 ≥ 0; H1 ∶ μ1 − μ2 < 0, which of the following is an equivalent statement? (More than one choice is possible.)a) H0 ∶ μ1 − μ2 < 0; H1 ∶ μ1 − μ2 ≥
- If X̅1 = 17.50, n1 = 100, σ1 = 2.07, X̅2 = 10.15, n2 = 100, and σ2 = 1.25.a) Construct a two-sided 90% confidence interval for μ1 − μ2.b) Interpret the confidence interval.
- If X̅1 = 199.61, n1 = 75, σ21 = 25, X̅2 = 203.27, n2 = 75, and σ22 = 25.a) Construct a two-sided 90% confidence interval for μ1 − μ2.b) Interpret the confidence interval.
- Find the standard deviation of X̅1 - X̅2 whena) n1 = 115, σ1 = 37, n2 = 88, σ2 = 52.b) n1 = 33, σ1 = 61, n2, = 94, σ2 = 59.
- Find the standard deviation of X̅1 - X̅2 whena) n1 = 50, σ21 = 25, n2 = 65, σ22 = 25.b) n1 = 200, σ21 = 100, n2, = 150, σ22 = 47.
- If you were given the regression equation Ŷ = 4 + 500x and told that since the slope is 500 there is a strong linear association between the two variables, what would you say?
- A popular way to measure the volatility of a financial asset, such as a stock, is its beta value. If Y = daily return of an asset, and X = daily return of the S&P 500 index fund (the market),
- A new analyst has been hired and you have been asked to take him under your wing. To get things started, you ask him to check if there is an association between two variables X and Y. After a few
- In the figures below, determine if the estimated slope of a simple linear regression line will be negative, positive, or close to zero. (a) Y (d) lo 00 Soo 000
- If Ŷ = 3.5 − 7.34X,a) Interpret the value of the slope.b) Estimate the mean of the response variable when x = 10.25.
- If Ŷ = −0.5 + 11.6X,a) Interpret the value of the slope.b) Estimate the mean of the response variable when x = 0.48.
- When β1 = −105.41, what happens to the response variable as X increases?
- When β1 = 12, what happens to the response variable as X increases?

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