The manufacturer of Boston and Vermont asphalt shingles provides its customer with a 20-year warranty on most of its products. To determine whether a shingle will last through the warranty period, accelerated-life testing is conducted at the manufacturing plant. Accelerated-life testing exposes the shingle to the stresses it would be subject to in lifetime of normal use in a laboratory setting via an experiment that takes only a few minutes to conduct. In this test, a shingle is repeatedly scraped with a brush for a short period of time, and the shingle granules removed by the brushing are weighed (in grams). Shingles that experience low amounts of granule loss are expected to last longer in normal use than shingles that experience high amounts of granule loss. The file Granule contains a sample of 170 measurements made on the company’s Boston shingles and 140 measurements made on Vermont shingles.
a. For the Boston shingles, is there evidence at the 0.05 level of significance that the population
b. Interpret the meaning of the p-value in (a).
c. For the Vermont shingles, is there evidence at the 0.05 level of significance that the population mean granule loss is different from 0.30 grams?
d. Interpret the meaning of the p-value in (c).
e. In (a) through (d), do you have to be concerned with the normality assumption? Explain.
Want to see the full answer?
Check out a sample textbook solutionChapter 9 Solutions
EP BASIC BUS.STATS-ACCESS (18 WEEKS)
- Is carbon dating? Why does it work? Give an example in which carbon dating would be useful.arrow_forwardTen years ago, the town of Easton decided to increase its annual spending on education so that its high school graduates would be able to earn higher wages. Now Easton has asked you to evaluate the effectiveness of the spending increase. Their data show that before the spending increase, the average annual salary of recent high school graduates was $25,000 and that now that average salary has risen to $28,500. Fortunately for your analysis, a neighboring community (Allentown) did not change its annual spending on education. Ten years ago, recent Allentown high school graduates earned an average of $22,500, and now that average is $23,750. (a) Use a difference-in-differences estimator to determine whether Easton’s spending increase caused the wages of their high school graduates to increase. please provide an accurate answer.arrow_forwardArchaeoloaists used pièces of burned wood, or charcoal, found at the site to date prehistoric paintings and drawings on walls and ceilings of a cave in Lascaux, France. Use the information in Example 3 or Section 3.1 to determine the appropriate age of a piece of burned wood, if it was found that 83% of the C-14 found in living trees of the same type had decayed. (Round your answer to the neares hundred years.arrow_forward
- Ten years ago, the town of Easton decided to increase its annual spending on education so that its high school graduates would be able to earn higher wages. Now Easton has asked you to evaluate the effectiveness of the spending increase. Their data show that before the spending increase, the average annual salary of recent high school graduates was $25,000 and that now that average salary has risen to $28,500. Fortunately for your analysis, a neighboring community (Allentown) did not change its annual spending on education. Ten years ago, recent Allentown high school graduates earned an average of $22,500, and now that average is $23,750. (b) What underlying assumption do you have to make in order for your estimate to be valid? What might cause your underlying assumption to be invalid?arrow_forwardSome commercial airlines recirculate about half the air in the cabin during flights as a way to improve fuel efficiency. Other airlines make a policy of NOT recirculating the air and instead, have fresh air from the atmosphere constantly being inserted into the cabin with the “old” air being pumped out of the plane. A total of 1100 passengers flying from San Francisco to Denver were used for an experiment. After their flight, they were each given a list of symptoms associated with the common cold. They were asked to report if they experienced cold symptoms within 24 hours of the flight landing. Of the 517 passengers who flew on planes that recirculate the air, 108 reported post-flight cold symptoms. Of the 583 passengers who flew on airlines that do not use recirculation in the cabin, 110 reported symptoms. Suppose now that we want to use the recirculation of air data to explore “Goal #2”, which is to resolve a hypothesis test about . a) If we want to resolve this hypothesis…arrow_forwardArchaeologists used pieces of burned wood, or charcoal, found at the site to date prehistoric paintings and drawings on walls and ceilings of a cave in Lascaux, France. Use the information in Example 3 of Section 3.1 to determine the appropriate age of a piece of burned wood, if it was found that 86% of the C-14 found in living trees of the same type had decayed, (Round ******. your answer to the nearest hundred years.) years Need Help? Raad It Submit Answerarrow_forward
- An article in Quality Engineering presents viscosity data from a batch chemical process. A sample of these data is in the table. Reading left to right and up to down, draw a time series plot of all the data and comment on any features of the data that are revealed by this plot. Consider that the first 40 observations (the first 4 columns) were generated from a specific process, whereas the last 40 observations were generated from a different process. Does the plot indicate that the two processes generate similar results? Calculate the sample mean and sample variance of the first 40 and the second 40 observations.arrow_forwardThe SAT and ACT exams are often used to predict a student's first-term college grade point average (GPA). Different formulas are used for different colleges and majors. Suppose that a student is applying to a university with an intended major in civil engineering. Also suppose that for this college and this major, the following model is used to predict first term GPA. GPA = a + b(ACT) a = 0.6 b = 0.2 (a) In this context, what would be the appropriate interpretation of the value of a? The value of a is the predicted ACT score of a student who has a 0 GPA. There is not enough information to know how to interpret the value of a. The value of a represents the change in predicted GPA associated with an increase of 1 in ACT score. The value of a represents the change in predicted GPA associated with an decrease of 1 in ACT score. The value of a is the predicted GPA of a student who scored a 0 on the ACT. (b) In this context, what would be the…arrow_forwardA study is run to evaluate the effectiveness of an exercise program in reducing systolic Ate blood pressure in patients with pre-hypertension. A total of 15 patients with pre- 12 hypertension enrolled in the study, and their systolic blood pressures are measured. Each patient then participated in an exercise training program where they learned proper techniques and execution of a series of exercises. Patients were instructed to do the exercise program three times per week for six weeks. After six weeks, systolic blood pressures were again measured, and data were recorded. This study sought to determine if there is a difference in systolic blood pressures after participating in the exercise program as compared to before. What is the most appropriate statistical test to be used to answer the research objectives? a. Spearman Correlation Coefficient b. Pearson Correlation Coefficient c. Wilcoxon Signed Ranks Test d. Mann-Whitney U Testarrow_forward
- Cellulon, a manufacturer of home insulation, wants to develop guidelines for builders and consumers on how the thickness of the insulation in the attic of a home and the outdoor temperature affect natural gas consumption. In the laboratory, it varied the insulation thickness and temperature. A few of the findings are:arrow_forwardSusan Sound predicts that students will learn most effectively with a constant background sound, as opposed to an unpredictable sound or no sound at all. She randomly divides twenty-four students into three groups of eight. All students study a passage of text for 30 minutes. Those in group 1 study with background sound at a constant volume in the background. Those in group 2 study with noise that changes volume periodically. Those in group 3 study with no sound at all. After studying, all students take a 10 point multiple choice test over the material. Their scores follow: Group test scores 1) constant sound 7 4 6 8 6 6 2 9 2) random sound 5 5 3 4 4 7 2 2 3) no sound 2 4 7 1 2 1 5 5 Calculate the Between-Subject One-Way ANOVA, make sure you include all the steps and show your calculations. Determine if you need a post hoc analysis, if so, complete the post-hoc analysis Interpret the results of your statistical…arrow_forwardDoctors Jonert and Eckson were excited about their results of their previous study on Gypsy moth development. They decided to continue their study of moths, expanding it to native Virginia moths to learn about the pupal mass relationship to development. As part of their study they have a colony of Pink-striped Oakworm moths that have been raised in a controlled environment in their labs. They have collected several pieces of data about the male Luna moths in their colony in order to determine if the pupal mass of the males was related to their rate of development. 17) Looking at the graph on Pupal Mass vs Development Time, what type of graph is this? (pie chart, column chart, bar chart, histogram, line graph, scatter plot, area chart.) 18) Using the appropriate formula, calculate the covariance to 3 decimals. covariance = , now convert it to a percentage: % 19) Is the covariance positive, negative or zero? . 20) Are the variables dependent on one another? (yes, no) 21) Using the…arrow_forward
- Algebra & Trigonometry with Analytic GeometryAlgebraISBN:9781133382119Author:SwokowskiPublisher:Cengage