According to the National Survey of Student Engagement, the average student spends about 15 hours each week preparing for classes; preparation for classes includes homework, reading and any other assignments. Source: Data extracted from bit.ly/2qSNwNo. Assume the standard deviation of time spent preparing for classes is 4 hours. If you select a random sample of 16 students, a. what is the probability that the mean time spent preparing for classes is at least 14 hours per week? b. there is an 85% chance that the sample mean is less than how many hours per week? c. What assumption must you make in order to solve (a) and (b)? d. If you select a random sample of 64 students, there is an 85% chance that the sample mean is less than how many hours per week?
> The Consumer Financial Protection Bureau reports on consumer financial product and service complaint submissions by state, category, and company. The following table, stored in FinancialComplaints1 , represents complaints received from Louisiana consumer
> The following table, stored in Smartphone Sales , represents the annual market share of smartphones, by type, for the years 2011, 2012, 2013, 2014, and 2015. Source: Data extracted from www.gartner.com/newsroom/id/3215217. a. What conclusions can you r
> The following data represent the responses to two questions asked in a survey of 40 college students majoring in business: What is your gender? (M = male; F = female) and What is your major? (A = Accounting; C = Computer Information Systems; a. Tally t
> A categorical variable has three categories, with the following frequencies of occurrence: a. Compute the percentage of values in each category. b. What conclusions can you reach concerning the categories?
> Four different beverages are sold at a fast-food restaurant: soft drinks, tea, coffee, and bottled water. a. Explain why the type of beverage sold is an example of a categorical variable. b. Explain why the type of beverage is an example of a nominal-s
> A political pollster is conducting an analysis of sample results in order to make predictions on election night. Assuming a two-candidate election, if a specific candidate receives at least 55% of the vote in the sample, that candidate will be forecast a
> Social media provides an enormous amount of data about the activities and habits of people using social platforms like Facebook and Twitter. The belief is that mining that data provides a treasure trove for those who seek to quantify and predict future h
> Three professors examined awareness of four widely disseminated retirement rules among employees at the University of Utah. These rules provide simple answers to questions about retirement planning (R. N. Mayer, C. D. Zick, and M. Glaittle, “Public Aware
> Download and examine Zarca Interactive’s “Sample Survey for Associations/Sample Questions for Surveys for Associations,” available at bit.ly/2p5HlGO. a. Give an example of a categorical variable included in the survey. b. Give an example of a numerical v
> The American Community Survey (www.census.gov/acs) provides data every year about communities in the United States. Addresses are randomly selected and respondents are required to supply answers to a series of questions. a. Describe a variable for which
> A recent PwC survey of 1,379 CEOs from a wide range of industries representing a mix of company sizes from Asia, Europe, and the Americas indicated that CEOs are firmly convinced that it is harder to gain and retain people’s trust in an increasingly digi
> The Gallup organization releases the results of recent polls on its website, www.gallup.com. Visit this site and read an article of interest. a. Describe the population of interest. b. Describe the sample that was collected. c. Describe a parameter of in
> Results of a 2017 Computer Services, Inc. (CSI) survey of a sample of 163 bank executives reveal insights on banking priorities among financial institutions (goo.gl/mniYMM). As financial institutions begin planning for a new year, of utmost importance is
> Visit the official website for Microsoft Excel, products .office.com/excel or Minitab (www.minitab.com) or JMP (www .jmp.com). Review the features of the program you chose and then state the ways the program could be useful in statistical analysis.
> A survey indicates that the vast majority of college students own their own smartphones. What information would you want to know before you accepted the results of this survey?
> A hotel management company runs 10 hotels in a resort area. The hotels have a mix of pricing—some hotels have budget-priced rooms, some have moderate-priced rooms, and some have deluxe-priced rooms. Data are collected that indicate the number of rooms th
> The following data represent the responses (Y for yes and N for no) from a sample of 40 college students to the question “Do you currently own shares in any stocks?” N N Y N N Y N Y N Y N N Y N Y Y N N N Y N Y N N N N Y N N Y Y N N N Y N N Y N N a. Deter
> An amusement park company owns three hotels on an adjoining site. A guest relations manager wants to study the time it takes for shuttle buses to travel from each of the hotels to the amusement park entrance. Data were collected on a particular day that
> The amount of monthly data usage by a sample of 10 cellphone users (in MB) was: 0.4, 2.7MB, 5.6, 4.3, 11.4, 26.8, 1.6, 1,079, 8.3, 4.2 Are there any potential irregularities in the data?
> The cellphone brands owned by a sample of 20 respondents were: Apple, Samsung, Appel, Nokia, Blackberry, HTC, Apple, Samsung, HTC, LG, Blueberry, Samsung, Samsung, APPLE, Motorola, Apple, Samsun, Apple, Samsung a. Clean these data and identify any irregu
> Suppose that 10,000 customers in a retailer’s customer database are categorized by three customer types: 3,500 prospective buyers, 4,500 first time buyers, and 2,000 repeat (loyal) buyers. A sample of 1,000 customers is needed. a. What type of sampling s
> Pre-numbered sales invoices are kept in a sales journal. The invoices are numbered from 0001 to 5000. a. Beginning in row 16, column 01, and proceeding horizontally in a table of random numbers (Table E.1), select a simple random sample of 50 invoice num
> The registrar of a university with a population of N = 4,000 full-time students is asked by the president to conduct a survey to measure satisfaction with the quality of life on campus. The following table contains a breakdown of the 4,000 registered ful
> A population has four members (called A, B, C, and D). You would like to select a random sample of n = 2, which you decide to do in the following way: Flip a coin; if it is heads, the sample will be items A and B; if it is tails, the sample will be items
> You want to select a random sample of n = 1 from a population of three items (which are called A, B, and C). The rule for selecting the sample is as follows: Flip a coin; if it is heads, pick item A; if it is tails, flip the coin again; this time, if it
> For a study that consists of personal interviews with participants (rather than mail or phone surveys), explain why simple random sampling might be less practical than some other sampling methods.
> Given a population of N = 93, starting in row 29, column 01 of the table of random numbers (Table E.1), and reading across the row, select a sample of N = 15 a. without replacement. b. with replacement.
> A random sample of 50 households was selected for a phone (landline and cellphone) survey. The key question asked was, “Do you or any member of your household own an Apple product (iPhone, iPod, iPad, or Mac computer)?” Of the 50 respondents, 20 said yes
> For a population of N = 902, verify that by starting in row 05, column 01 of the table of random numbers (Table E.1), you need only six rows to select a sample of N = 60 without replacement.
> For a population containing N = 902 individuals, what code number would you assign for a. the first person on the list? b. the fortieth person on the list? c. the last person on the list?
> Visit the home page of the Statistics Portal “Statista” at statista. com. Examine one of the “Popular infographic topics” in the Infographics section on that page. What type of data source is the information presented here based on?
> Transportation engineers and planners want to address the dynamic properties of travel behavior by describing in detail the driving characteristics of drivers over the course of a month. What type of data collection source do you think the transportation
> The director of market research at a large department store chain wanted to conduct a survey throughout a metropolitan area to determine the amount of time working women spend shopping for clothing in a typical month. a. Indicate the type of data the di
> If two students score a 90 on the same examination, what arguments could be used to show that the underlying variable—test score—is continuous?
> One of the variables most often included in surveys is income. Sometimes the question is phrased “What is your income (in thousands of dollars)?” In other surveys, the respondent is asked to “ Select the circle corresponding to your income level” and is
> Suppose the following information is collected from Robert Keeler on his application for a home mortgage loan at the Metro County Savings and Loan Association. a. Monthly payments: $2,227 b. Number of jobs in past 10 years: 1 c. Annual family income:
> For each of the following variables, determine whether the variable is categorical or numerical and determine its measurement scale. If the variable is numerical, determine whether the variable is discrete or continuous. a. Amount of money spent on clot
> Referring to the results from Problem 2.100 on page 86 concerning the weights of Boston and Vermont shingles, write a report that evaluates whether the weights of the pallets of the two types of shingles are what the company expects. Be sure to incorpora
> In a random sample of 64 people, 48 are classified as “successful.” a. Determine the sample proportion, p, of “successful” people. b. If the population proportion is 0.70, determine the standard error of the proportion.
> For each of the following variables, determine whether the variable is categorical or numerical and determine its measurement scale. If the variable is numerical, determine whether the variable is discrete or continuous. a. Name of Internet service prov
> The following information is collected from students upon exiting the campus bookstore during the first week of classes. a. Amount of time spent shopping in the bookstore b. Number of textbooks purchased c. Academic major d. Gender Classify each vari
> A/B testing allows businesses to test a new design or format for a web page to determine if the new web page is more effective than the current one. Web designers decide to create a new call-to-action button for a web page. Every visitor to the web page
> The file Currency contains the exchange rates of the Canadian dollar, the Japanese yen, and the English pound from 1980 to 2016, where the Canadian dollar, the Japanese yen, and the English pound are expressed in units per U.S. dollar. a. Construct time-
> The data stored in Drink represent the amount of soft drink in a sample of 50 consecutively filled 2-liter bottles. a. Construct a time-series plot for the amount of soft drink on the Y axis and the bottle number (going consecutively from 1 to 50) on the
> The file Natural Gas contains the U.S. monthly average commercial and residential price for natural gas in dollars per thousand cubic feet from January 2008 through December 2016. Source: Data extracted from “U.S. Natural Gas Prices,” bit.ly/2oZIQ5Z, acc
> The file Protein contains calorie and cholesterol information for popular protein foods (fresh red meats, poultry, and fish). Source: U.S. Department of Agriculture. a. Construct frequency and percentage distributions for the number of calories. b. Const
> What was the average price of a room at two-star, three-star, and four-star hotels around the world during 2016? The file Hotel Prices contains the average hotel room prices in Canadian dollars (about U.S. $0.75 as of December 2016) per night paid by Can
> Studies conducted by a manufacturer of Boston and Vermont asphalt shingles have shown product weight to be a major factor in customers’ perception of quality. Moreover, the weight represents the amount of raw materials being used and is therefore very im
> The file CEO2016 includes the total compensation (in $millions) for CEOs of 200 S&P 500 companies and the one-year total shareholder return in 2016. Source: Data extracted from bit.ly/1QqpEUZ. For total compensation: a. Construct a frequency distributi
> Given a normal distribution with m = 50 and s = 5, if you select a sample of n = 100, what is the probability that X is a. less than 47? b. between 47 and 49.5? c. above 51.1? d. There is a 35% chance that X is above what value?
> Given a normal distribution with m = 100 and s = 10, if you select a sample of n = 25, what is the probability that X is a. less than 95? b. between 95 and 97.5? c. above 102.2? d. There is a 65% chance that X is above what value?
> A runner sprints around a circular track of radius 100 m at a constant speed of 7 m/s. The runner’s friend is standing at a distance 200 m from the center of the track. How fast is the distance between the friends changing when the distance between them
> Find the absolute maximum and absolute minimum values of f on the given interval. f(a) — 5 + 54х — 2х', [0,4]
> Find the critical numbers of the function. f (x) = x2e-3x
> Find the critical numbers of the function. F (x) = x4/5 (x – 4)2
> Find the critical numbers of the function. h (p) = p - 1/p2 + 4
> Find the critical numbers of the function. h (t) = t3/4 - 2t 1/4
> Find the critical numbers of the function. g (y) = y - 1/y2 - y + 1
> (a). Sketch the graph of a function that has two local maxima, one local minimum, and no absolute minimum. (b). Sketch the graph of a function that has three local minima, two local maxima, and seven critical numbers.
> Find the critical numbers of the function. g (t) = |3t – 4|
> Find the critical numbers of the function. s (t) = 3t4 + 4t3 - 6t2
> For each of the numbers a, b, c, d, r, and s, state whether the function whose graph is shown has an absolute maximum or minimum, a local maximum or minimum, or neither a maximum nor a minimum. yA 0 a b c dr
> Two carts, A and B, are connected by a rope 39 ft long that passes over a pulley P (see the figure). The point Q is on the floor 12 ft directly beneath P and between the carts. Cart A is being pulled away from Q at a speed of 2 ft/s. How fast is cart B m
> If a snowball melts so that its surface area decreases at a rate of 1 cm2/min, find the rate at which the diameter decreases when the diameter is 10 cm. (a). What quantities are given in the problem? (b). What is the unknown? (c). Draw a picture of the s
> Sketch the graph of a function f that is continuous on [1, 5] and has the given properties. f has no local maximum or minimum, but 2 and 4 are critical numbers
> Sketch the graph of a function f that is continuous on [1, 5] and has the given properties. Absolute maximum at 5, absolute minimum at 2, local maximum at 3, local minima at 2 and 4
> (a). Find the intervals on which f is increasing or decreasing. (b). Find the local maximum and minimum values of f. (c). Find the intervals of concavity and the inflection points. f (x) = x2/x2 + 3
> Find the critical numbers of the function. f (x) = x3 + 6x2 - 15x
> Sketch the graph of a function f that is continuous on [1, 5] and has the given properties. Absolute minimum at 1, absolute maximum at 5, local maximum at 2, local minimum at 4
> (a). Sketch the graph of a function on [-1, 2] that has an absolute maximum but no local maximum. (b). Sketch the graph of a function on [-1, 2] that has a local maximum but no absolute maximum.
> (a). Sketch the graph of a function that has a local maximum at 2 and is differentiable at 2. (b). Sketch the graph of a function that has a local maximum at 2 and is continuous but not differentiable at 2. (c). Sketch the graph of a function that has a
> Let f (t) be the temperature at time where you live and suppose that at time t =3 you feel uncomfortably hot. How do you feel about the given data in each case? (а) f'(3) — 2, f"(3) — 4 (Б) f (3) — 2, f"(3) — —4 (c) f'(3) = -2, f"(3) = 4 (d) f'(3) =
> If z2 = x2 + y2, dx/dt = 2, and dy/dt = 3, find dz/dt when x = 5 and y = 12.
> If x2 + y2 = 25 and dy/dt = 6, find dx/dt when y = 4.
> Sketch the graph of a function f that is continuous on [1, 5] and has the given properties. Absolute minimum at 2, absolute maximum at 3, local minimum at 4
> C (x) = x1/3 (x + 4) (a). Find the intervals of increase or decrease. (b). Find the local maximum and minimum values. (c). Find the intervals of concavity and the inflection points. (d). Use the information from parts (a)–(c) to sketch the graph. Check
> Suppose y = √2x + 1, where x and y are functions of t. (a). If dx/dt = 3, find dy/dt when x = 4. (b). If dy/dt = 5, find dx/dt when x = 12.
> The radius of a sphere is increasing at a rate of 5 mm/s. How fast is the volume increasing when the diameter is 80 mm?
> A cylindrical tank with radius 5 m is being filled with water at a rate of 3 m3/min. How fast is the height of the water increasing?
> A plane flying horizontally at an altitude of 1 mi and a speed of 500 mi/h passes directly over a radar station. Find the rate at which the distance from the plane to the station is increasing when it is 2 mi away from the station. (a). What quantities a
> Two people start from the same point. One walks east at 3 mi/h and the other walks northeast at 2 mi/h. How fast is the distance between the people changing after 15 minutes?
> A plane flying with a constant speed of 300 km/h passes over a ground radar station at an altitude of 1 km and climbs at an angle of 300. At what rate is the distance from the plane to the radar station increasing a minute later?
> Find the absolute maximum and absolute minimum values of f on the given interval. x? - 4 f(x) = [-4, 4] x² + 4'
> A Ferris wheel with a radius of 10m is rotating at a rate of one revolution every 2 minutes. How fast is a rider rising when his seat is 16 m above ground level?
> (a). Find the intervals on which f is increasing or decreasing. (b). Find the local maximum and minimum values of f. (c). Find the intervals of concavity and the inflection points. f (x) = x4 - 2x2 + 3
> The length of a rectangle is increasing at a rate of 8 cm/s and its width is increasing at a rate of 3 cm/s. When the length is 20 cm and the width is 10 cm, how fast is the area of the rectangle increasing?
> A plane flies horizontally at an altitude of 5km and passes directly over a tracking telescope on the ground. When the angle of elevation is π/3, this angle is decreasing at a rate of π/6 rad/min. How fast is the plane traveling at that time?
> A lighthouse is located on a small island 3 km away from the nearest point P on a straight shoreline and its light makes four revolutions per minute. How fast is the beam of light moving along the shoreline when it is 1 km from P?
> B (x) = 3x2/3 - x (a). Find the intervals of increase or decrease. (b). Find the local maximum and minimum values. (c). Find the intervals of concavity and the inflection points. (d). Use the information from parts (a)–(c) to sketch the graph. Check you
> Use the graph to state the absolute and local maximum and minimum values of the function. y=g(x) 1
> A television camera is positioned 4000 ft from the base of a rocket launching pad. The angle of elevation of the camera has to change at the correct rate in order to keep the rocket in sight. Also, the mechanism for focusing the camera has to take into a
> Find the critical numbers of the function. f (x) = 4 + 1/3 x – 1/2 x2
> Brain weight B as a function of body weight W in fish has been modeled by the power function B = 0.007W2/3, where B and W are measured in grams. A model for body weight as a function of body length L (measured in centimeters) is W = 0.12L2.53. If, over 1
> Sketch the graph of f by hand and use your sketch to find the absolute and local maximum and minimum values of f. (Use the graphs and transformations of Sections 1.2 and 1.3.) _f(x) = In x, 0<xs 2
> If two resistors with resistances R1 and R2 are connected in parallel, as in the figure, then the total resistance R, measured in ohms (â„¦), is given by 1/R = 1/R1 + 1/R2. If R1 and R2 are increasing at rates of 0.3â„¦
> When air expands adiabatically (without gaining or losing heat), its pressure P and volume V are related by the equation PV1.4 = C, where C is a constant. Suppose that at a certain instant the volume is 400 cm3 and the pressure is 80 kPa and is decreasin
> Boyle’s Law states that when a sample of gas is compressed at a constant temperature, the pressure P and volume V satisfy the equation PV = C, where C is a constant. Suppose that at a certain instant the volume is 600 cm3, the pressure is 150 kPa, and th
> Two sides of a triangle have lengths 12 m and 15 m. The angle between them is increasing at a rate of 20/min. How fast is the length of the third side increasing when the angle between the sides of fixed length is 600?
> Two sides of a triangle are 4 m and 5 m in length and the angle between them is increasing at a rate of 0.06 rad/s. Find the rate at which the area of the triangle is increasing when the angle between the sides of fixed length is π/3.
> (a). Find the intervals on which f is increasing or decreasing. (b). Find the local maximum and minimum values of f. (c). Find the intervals of concavity and the inflection points. f (x) = 4x3 + 3x2 - 6x + 1