Average talk time between charges of a cell phone is advertised as 4 hours. Assume that talk time is normally distributed with a standard deviation of 0.8 hour. a. Find the probability that talk time...
The amounts of sugar (grams of sugar per gram of cereal) and calories (per gram of cereal) were recorded for a sample of 16 different cereals. TI-83/84 Plus calculator results are shown here. Is...
One of the cars sold by Walts car dealership is a very popular subcompact car called Rhino. The final sale price of the basic model of this car varies from customer to customer depending on the...
Over the past few years the percentage of students who leave Lakeland College at the end of the first year has increased. Last year Lakeland started a voluntary one-week orientation program to help...
Let x be a random variable that represents hemoglobin count (HC) in grams per 100 milliliters of whole blood. Then x has a distribution that is approximately normal, with population mean of about 14...
Consumers spend an average of $21 per week in cash without being aware of where it goes (data extracted from "Snapshots: A Hole in Our Pockets," USA Today, January 18, 2010, p. 1A). Assume that the...
Consider babies born in the "normal" range of 37-43 weeks gestational age. Extensive data supports the assumption that for such babies born in the United States, birth weight is normally distributed...
Spam e-mail has become a serious and costly nuisance. An office manager believes that the average amount of time spent by office workers reading and deleting spam exceeds 25 minutes per day. To test...
The data from exercise 3 follow. The estimated regression equation for these data is y = 7.6 + .9x. What percentage of the total sum of squares can be accounted for by the estimated regression...
In 2007, Apple stock had a mean daily volume of 35.1 million shares, according to Yahoo!Finance. A random sample of 40 trading days in 2010 resulted in a sample mean of 23.6 million shares with a...
In Olympic running events, preliminary heats are determined by random draw, so we should expect the ability level of runners in the various heats to be about the same, on average. The table gives the...
The following questions refer to a capital budgeting problem with six projects represented by binary variables x1, x2, x3, x4, x5, and x6. a. Write a constraint modeling a situation in which two of...
The Excel file HATCO consists of data related to predict predicting the level of business (Usage Level) obtained from a survey of purchasing managers of customers of an industrial supplier, HATCO....
Find the mean and standard deviation for the numbers of girls in 8 births. Refer to the accompanying table, which describes results from groups of 8 births from 8 different sets of parents. The...
The time between surface finish problems in a galvanizing process is exponentially distributed with a mean of 40 hours. A single plant operates three galvanizing lines that are assumed to operate...
The U.S. Energy Information Administration (US EIA) reported that the average price for a gallon of regular gasoline is $3.94 (US EIA website, April 6, 2012). The US EIA updates its estimates of...
According to the Crown ATM Network, the mean ATM withdrawal is $67. PayEase, Inc., manufacturers an ATM that allows one to pay bills (electric, water, parking tickets, and so on), as well as withdraw...
A fraction nonconforming control chart has center line 0.01, UCL = 0.0399, LCL = 0, and n = 100. If three-sigma limits are used, find the smallest sample size that would yield a positive lower...
Survey evidence is often introduced in court cases involving trademark violation and employment discrimination. There has been controversy, however, about whether non probability samples are...
Nutri-Jenny is a weight-management center. It produces a wide variety of frozen entrées for consumption by its clients. The entrées are strictly monitored for nutritional content to...
An Izod impact test was performed on 20 specimens of PVC pipe. The sample mean is X = 1.25 and the sample standard deviation is x = 0.25. Find a 99% lower confidence bound on Izod impact strength.
The motion of a spring that is subject to a frictional force or a damping force (such as a shock absorber in a car) is often modeled by the product of an exponential function and a sine or cosine...
Internet Magazine monitors Internet service providers (ISPs) and provides statistics on their performance. The average time to download a Web page for free ISPs is approximately 20 seconds for...
Harris Segal, marketing director for North-Central Power and Light, is about to begin an advertising campaign promoting energy conservation. In trying to budget between television and newspaper...
Control charts for x and R are to be established to control the tensile strength of a metal part. Assume that tensile strength is normally distributed. Thirty samples of size n= 6 parts are collected...
Consumer complaints are frequently reported to the Better Business Bureau. Industries with the most complaints to the Better Business Bureau are often banks, cable and satellite television companies,...
For each research finding, decide whether there is evidence of causation, correlation, or both. If it is only a correlation, name a possible lurking variable that may be the cause of the results. a....
The following data represent tonnes of wheat harvested each year (1894-1925) from Plot 19 at the Rothamsted Agricultural Experiment Stations, England. (a) Multiply each data value by 100 to "clear"...
A window has the shape of a square surmounted by a semicircle. The base of the window is measured as having width 60 cm with a possible error in measurement of 0.1 cm. Use differentials to estimate...
A two-dimensional circular cylinder is placed in a high-speed uniform flow. Vortices shed from the cylinder at a constant frequency, and pressure sensors on the rear surface of the cylinder detect...
Newton Manufacturing produces scientific calculators. The models are N350, N450, and the N900. Newton has planned its distribution of these products around eight customer zones: Brazil, China,...
A sample of 80 results in 30 successes. a. Calculate the point estimate for the population proportion of successes. b. Construct 90% and 99% confidence intervals for the population proportion. c. Can...
Given a random sample size of n = 900 from a binomial probability distribution with P = 0.50 do the following: a. Find the probability that the number of successes is greater than 500. b. Find the...
A sociologist claims that children ages 1214 spent less time sleeping in 1981 than children ages 1214 do today. A study was conducted in 1981 to find the time that children ages 1214 spent sleeping...
Required Tasks: - Assuming that incomes can be approximated using a normal distribution with the specified mean and standard deviation, calculate the income that cut off the bottom 10% of incomes. -...
A woman inherited $356,000. As she had no immediate need for the money at the time she inherited, she decided to invest some or all of it on January 1, 20In, with a goal of making the money grow to...
You work in the corporate office for a nationwide convenience store franchise that operates nearly 10,000 stores. The per-store daily customer count has been steady, at 900, for some time (i.e., the...
Use the data in PNTSPRD.RAW for this exercise. (i) The variable sprdcvr is a binary variable equal to one if the Las Vegas point spread for a college basketball game was covered. The expected value...
The sodium content of thirty 300-gram boxes of organic corn flakes was determined. The data (in milligrams) are as follows: 131.15, 130.69, 130.91, 129.54, 129.64, 128.77, 130.72, 128.33, 128.24,...
ALas Vegas roulette wheel has 38 different numerical values. If an individual bets on one number and wins, the payoff is 35 to 1. a. Show a payoff table for a $10 bet on one number for decision...
In a medium-sized southern city, 86 houses are for sale, each having about 2000 square feet of floor space. The asking prices vary. The frequency distribution shown contains the price categories for...
When one company buys another company, it is not unusual that some workers are terminated. The severance benefits offered to the laid-off workers are often the subject of dispute. Suppose that the...
The following data represent commute times (in minutes) and score on a well-being survey. Commute Time Gallup-Healthways Well-Being (minutes), x ....... Index Composite Score, y 5 .......... 69.2 15...
The file Sedans contains the overall miles per gallon (MPG) of 2014 midsized sedans: a. Construct a 95% confidence interval estimate for the population mean MPG of 2014 midsized sedans, assuming a...
A university administrator has collected data on total Scholastic Aptitude Test (SAT) score versus freshman grade point average (GPA) for a sample of students who recently finished their first year...
(a) Program a calculator or computer to use Eulers method to compute y(1), where y(x) is the solution of the initial-value problem (i) h = 1 (ii) h = 0.1 (iii) h = 0.01 (iv) h = 0.001 (b) Verify that...
The Seneca Childrens Fund (SCF) is a local charity that runs a summer camp for disadvantaged children. The funds board of directors has been working very hard over recent years to decrease the amount...
A random sample of six salespeople who attended a motivational course on sales techniques was monitored 3 months before and 3 months after the course. The table shows the values of sales (in...
The object of a general chemistry experiment is to determine the amount (in milliliters) of sodium hydroxide (NaOH) solution needed to neutralize 1 gram of a specified acid. This will be an exact...
The National Credit Union has $250,000 available to invest in a 12-month commitment. The money can be placed in Treasury notes yielding an 8% return or in municipal bonds at an average rate of return...
Time magazine article about a survey of men's attitudes reported that 11 of 161 black respondents and 20 of 358 Latino respondents responded "Yes" to the question "Are you a stay-at-home dad?" How...
An investment opportunity boasts that the chance of doubling your money in 3 years is 95%. However, when you research the details of the investment, you estimate that there is a 3% chance that you...
An automotive parts company has been besieged with poor publicity over the past few years due to several highly publicized product recalls which have tarnished its public image. This has prompted a...
The probability that a student fails the screening test for scoliosis (curvature of the spine) at a local high school is known to be 0.004. Of the next 1875 students who are screened for scoliosis,...
Osteoporosis is a degenerative disease that primarily affects women over the age of 60. A research analyst wants to forecast sales of StrongBones, a prescription drug for treating this debilitating...
You now have $3000. You will toss a fair coin four times. Before each toss you can bet any amount of your money (including none) on the outcome of the toss. If heads comes up, you win the amount you...
A random sample of weekly work logs at an automobile repair station was obtained, and the average number of customers per day was recorded. Use a normal probability plot to assess whether the sample...
Hayes (2000) took a stratified sample of New York City food stores. The sampling frame consisted of 1408 food stores with at least 4000 square feet of retail space. The population of stores was...
Because of a sluggish economy, Bechtold Construction has been forced to modify its plans for the housing development in Problem 11-9. The result is that the path from node 6 to 7 now has a distance...
Some fast-food chains offer a lower-priced combination meal in an effort to attract budget-conscious customers. One chain test-marketed a burger fries and a drink combination for $1.71. The weekly...
Consider the following hypotheses: H0: p 0.38 HA: p < 0.38 Compute the p-value based on the following sample information. a. x = 22; n = 74 b. x = 110; n = 300 c. = 0.34; n = 50 d. = 0.34; n = 400
A business analyst was interested in the relationship between a company's sales and its profits. She collected data (in millions of dollars) from a random sample of Fortune 500 companies and created...
A manufacturer of electroluminescent lamps knows that the amount of luminescent ink deposited on one of its products is normally distributed with a mean of 1.2 grams and a standard deviation of 0.03...
Engineers and scientists use mass-spring models to gain insight into the dynamics of structures under the influence of disturbances such as earthquakes. Figure shows such a representation for a...
The J. Mehta Company's production manager is planning for a series of 1-month production periods for stainless steel sinks. The demand for the next 4 months is as follows: DEMAND FOR MONTH STAINLESS...
Suppose that the average time a fully charged 6 volt laptop battery will operate a computer is 3.2 hours and follows the exponential probability distribution. a. Determine the probability that the...
A study was conducted with vegetarians to see whether the number of grams of protein each ate per day was related to diastolic blood pressure. The data are given here. If there is a significant...
A charged rod of length produces an electric field at point P (a, b) given by where λ is the charge density per unit length on the rod and ε0 is the free space permittivity (see the...
A heated rod with a uniform heat source can be modeled with the Poisson equation, d2T/dx2 = (x) Given a heat source (x) = 25 and the boundary conditions, T(x = 0) = 40 and T(x = 10) = 200, solve for...
The Aluminum Association reports that the average American uses 56.8 pounds of aluminum in a year. A random sample of 51 households is monitored for one year to determine aluminum usage. If the...
According to a Michigan State University researcher, Americans are becoming increasingly polarized on issues pertaining to the environment. (news.msu.edu, April 19, 2011). It is reported that 70% of...
Find the probability that the number x of correct answers is fewer than 3. Assume that random guesses are made for five multiple-choice questions on an ACT test, so that there are n = 5 trials, each...
Annas project for her introductory statistics course was to compare the selling prices of textbooks at two Internet bookstores. She first took a random sample of 10 textbooks used that term in...
Education reform is one of the most hotly debated subjects on both state and national policy makers list of socioeconomic topics. Consider a linear regression model that relates school expenditures...
Use the methods of descriptive statistics presented in this chapter to summarize the data and comment on your findings. At a minimum, your report should include the following: 1. Descriptive...
1. Develop numerical summaries of the data. 2. Using overall score as the dependent variable, develop three scatter diagrams, one using price as the independent variable, one using the number of...
Elena conducts an experiment in which she ï¬lls up the gas tank on her Toyota Camry 40 times and records the miles per gallon for each ï¬ll- up. A histogram of the miles per gallon...
While browsing through the magazine rack at a bookstore, a statistician decides to examine the relationship between the price of a magazine and the percentage of the magazine space that contains...
A television manufacturer claims that (at least) 90% of its TV sets will need no service during the first 3 years of operation. A consumer agency wishes to check this claim, so it obtains a random...
The Toys-R-4-U Company has developed two new toys for possible inclusion in its product line for the upcoming Christmas season. Setting up the production facilities to begin production would cost...
Beer sales at the Shapiro One-Stop Store are analyzed using temperature and number of people (age 21 or over) on the street as independent variables. A random sample of 20 days is selected, and the...
The data in Table P-16 show seasonally adjusted quarterly sales for Dickson Corporation and for the entire industry for 20 quarters. a. Fit a linear regression model, and store the residuals. Plot...
University Ceramics manufactures plates, mugs, and steins that include the campus name and logo for sale in campus bookstores. The time required for each item to go through the two stages of...
A random sample of 100 Modern Art dining room tables that came off the firm's assembly line is examined. Careful inspection reveals a total of 2,000 blemishes. What are the 99.7% upper and lower...
A busy restaurant determined that between 6:30 P.M. and 9:00 P.M. on Friday nights, the arrivals of customers are Poisson distributed with an average arrival rate of 2.44 per minute. a. What is the...
A bowlers scores for six games were 182, 168, 184, 190, 170, and 174. Using these data as a sample, compute the following descriptive statistics: a. Range b. Variance c. Standard deviation d....
1. Use descriptive statistics to summarize the data from the two studies. What are your preliminary observations about the depression scores? 2. Use analysis of variance on both data sets. State the...
A consumer advocate claims that 80 percent of cable television subscribers are not satisfied with their cable service. In an attempt to justify this claim, a randomly selected sample of cable...
An insurance company has the business objective of reducing the amount of time it takes to approve applications for life insurance. The approval process consists of underwriting, which includes a...
Antonio runs a shoe repair store by himself. Customers arrive to bring a pair of shoes to be repaired according to a Poisson process at a mean rate of 1 per hour. The time Antonio requires to repair...
A recent study in the Journal of the American Medical Association (February 20, 2008) found that patients who go into cardiac arrest while in the hospital are more likely to die if it happens after...
The manufacturer of a daily dietary supplement claims that its product will help people lose weight. The company obtains a random sample of 950 adult males aged 20 to 74 who take the supplement and...
A marketing organization wishes to study the effects of four sales methods on weekly sales of a product. The organization employs a randomized block design in which three salesman use each sales...
Suppose that the number of asbestos particles in a sample of 1 squared centimeter of dust is a Poisson random variable with a mean of 1000. What is the probability that 10 squared centimeters of dust...
For the data in Problem 5-42, develop an exponential smoothing model with a smoothing constant of 0.3. Using the MSE, compare this with the model in Problem 5-42. In Problem 5-42, The following table...
The enrollment in the College of Business at Midwestern University by quarter from 2009 to spring 2013 is: Using the ratio-to-moving-average method: a. Determine the four quarterly indexes. b....
According to a survey of restaurant owners in the U.S. by Must Have Menus, 77% of restaurant owners believe that they need to use social media as a marketing tool. A different survey by the National...
A city in Ohio is considering replacing its fleet of gasoline-powered automobiles with electric cars. The manufacturer of the electric cars claims that this municipality will experience significant...
The Employment and Training Administration reported that the U.S. mean unemployment insurance benefit was $238 per week (The World Almanac, 2003). Are searcher in the state of Virginia anticipated...
Set up a tabular CUSUM scheme for the flow width data used in Example 6.1 (see Tables 6.1 and 6.2). When the procedure is applied to all 45 samples, does the CUSUM react more quickly than the x chart...