EBK STATISTICS FOR ENGINEERS AND SCIENT
4th Edition
ISBN: 8220100274381
Author: Navidi
Publisher: YUZU
expand_more
expand_more
format_list_bulleted
Concept explainers
Textbook Question
Chapter 8.3, Problem 18E
The article “Models for Assessing Hoisting Times of Tower Cranes” (A. Leung and C. Tam, Journal of Construction Engineering and Management, 1999: 385–391) presents a model constructed by a stepwise regression procedure to predict the time needed for a tower crane hoisting operation. Twenty variables were considered, and the stepwise procedure chose a nine-variable model. The adjusted R2 for the selected model was 0.73. True or false:
- a. The value 0.73 is a reliable measure of the goodness of fit of the selected model.
- b. The value 0.73 may exaggerate the goodness of fit of the model.
- c. A stepwise regression procedure selects only variables that are of some use in predicting the value of the dependent variable.
- d. It is possible for a variable that is of no use in predicting the value of a dependent variable to be part of a model selected by a stepwise regression procedure.
Expert Solution & Answer
Want to see the full answer?
Check out a sample textbook solutionStudents have asked these similar questions
Dental Hygiene: Which Toothbrush? In an experiment reported by J. Singer and D. Andrade in the article “Regression Models for the Analysis of Pretest/Posttest Data” (Biometrics, Vol. 53, pp. 729–735), the effect of using either a conventional or experimental (hugger) toothbrush was investigated. Twelve female and 12 male preschoolers were selected. Within each gender group, six were randomly assigned to the conventional toothbrush and the remaining six to the experimental toothbrush. After each subject brushed with the assigned toothbrush, a dental plaque index was measured. The higher the dental plaque index, the greater was the amount of plaque on an individual’s teeth.
a. Is the statistical design described here a completely randomized design or a randomized block design? Explain your answer.b. If the statistical design is a randomized block design, what are the blocks?
consider the coefficient estimates of the following market model linear regression of general motors (gm) on the S&P500 market returns
coefficient
estimate
std error
tvalue
pr(>ItI)
intercept
0.005860
0.0003704
1.582
0.12412
sp500
0.0904753
0.266702
3.392
0.00196
The number of observations is 32.At the 1% significance level, what is the (1)test statistic value,(2) the critical values (3) decision regarding the null hypothesis that the beta coefficient on the market returns is equal to 1.61
Computer output from a least-squares regression analysis based on a sample of size 17 is shown in the table.
Term
COEFCOEF
SE CoefSE Coef
TT
Constant
7.43
0.59
12.59
xx
5.65
1.14
6.45
Assuming all conditions for inference are met, which of the following defines a 95 percent confidence interval for the slope of the least-squares regression line?
Chapter 8 Solutions
EBK STATISTICS FOR ENGINEERS AND SCIENT
Ch. 8.1 - In an experiment to determine the factors...Ch. 8.1 - Prob. 2ECh. 8.1 - Prob. 3ECh. 8.1 - The article Application of Analysis of Variance to...Ch. 8.1 - Prob. 5ECh. 8.1 - Prob. 6ECh. 8.1 - Prob. 7ECh. 8.1 - Refer to Exercise 7. a. Find a 95% confidence...Ch. 8.1 - In a study of the lung function of children, the...Ch. 8.1 - Prob. 10E
Ch. 8.1 - Prob. 11ECh. 8.1 - The following MINITAB output is for a multiple...Ch. 8.1 - Prob. 13ECh. 8.1 - Prob. 14ECh. 8.1 - Prob. 15ECh. 8.1 - The following data were collected in an experiment...Ch. 8.1 - The November 24, 2001, issue of The Economist...Ch. 8.1 - The article Multiple Linear Regression for Lake...Ch. 8.1 - Prob. 19ECh. 8.2 - In an experiment to determine factors related to...Ch. 8.2 - In a laboratory test of a new engine design, the...Ch. 8.2 - In a laboratory test of a new engine design, the...Ch. 8.2 - The article Influence of Freezing Temperature on...Ch. 8.2 - The article Influence of Freezing Temperature on...Ch. 8.2 - The article Influence of Freezing Temperature on...Ch. 8.3 - True or false: a. For any set of data, there is...Ch. 8.3 - The article Experimental Design Approach for the...Ch. 8.3 - Prob. 3ECh. 8.3 - An engineer measures a dependent variable y and...Ch. 8.3 - Prob. 5ECh. 8.3 - The following MINITAB output is for a best subsets...Ch. 8.3 - Prob. 7ECh. 8.3 - Prob. 8ECh. 8.3 - (Continues Exercise 7 in Section 8.1.) To try to...Ch. 8.3 - Prob. 10ECh. 8.3 - Prob. 11ECh. 8.3 - Prob. 12ECh. 8.3 - The article Ultimate Load Analysis of Plate...Ch. 8.3 - Prob. 14ECh. 8.3 - Prob. 15ECh. 8.3 - Prob. 16ECh. 8.3 - The article Modeling Resilient Modulus and...Ch. 8.3 - The article Models for Assessing Hoisting Times of...Ch. 8 - The article Advances in Oxygen Equivalence...Ch. 8 - Prob. 2SECh. 8 - Prob. 3SECh. 8 - Prob. 4SECh. 8 - In a simulation of 30 mobile computer networks,...Ch. 8 - The data in Table SE6 (page 649) consist of yield...Ch. 8 - Prob. 7SECh. 8 - Prob. 8SECh. 8 - Refer to Exercise 2 in Section 8.2. a. Using each...Ch. 8 - Prob. 10SECh. 8 - The data presented in the following table give the...Ch. 8 - The article Enthalpies and Entropies of Transfer...Ch. 8 - Prob. 13SECh. 8 - Prob. 14SECh. 8 - The article Measurements of the Thermal...Ch. 8 - The article Electrical Impedance Variation with...Ch. 8 - The article Groundwater Electromagnetic Imaging in...Ch. 8 - Prob. 18SECh. 8 - Prob. 19SECh. 8 - Prob. 20SECh. 8 - Prob. 21SECh. 8 - Prob. 22SECh. 8 - The article Estimating Resource Requirements at...Ch. 8 - Prob. 24SE
Additional Math Textbook Solutions
Find more solutions based on key concepts
Use the model developed in Example 1.5 to predict the total sales for weeks 2 through 16, and compare the resul...
Business Analytics
To explain would this correlation increase, decrease or not change much if we remove the elephants.
Statistics Through Applications
the proportion of red cars in the sample and display the sampling distribution of the sample proportion on dot ...
PRACTICE OF STATISTICS F/AP EXAM
16. Singers The display shows the heights of some of the singers in a chorus, collected so that the singers cou...
STATS:DATA+MODELS-W/DVD
In Exercises 5-36, express all probabilities as fractions.
23. Combination Lock The typical combination lock us...
Essentials of Statistics, Books a la Carte Edition (5th Edition)
Teacher Salaries
The following data from several years ago represent salaries (in dollars) from a school distri...
Elementary Statistics: A Step By Step Approach
Knowledge Booster
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.Similar questions
- The following output was obtained from a multiple regression analysis. Analysis of variance SOURCE DF SS MS Regression 5 100 20 Residual Error 20 40 2 Total 25 140 Predictor Coefficient SE Coefficient t Constant 3.00 1.50 2.00 x1 4.00 3.00 1.33 x2 3.00 0.20 15.00 x3 0.20 0.05 4.00 x4 −2.50 1.00 −2.50 x5 3.00 4.00 0.75 Conduct a global test of hypothesis H0: β1 = β2 = β3 = β4 = β5 = 0; H1: Not all β's are 0 at the 0.05 significance level. d-1. State the decision rule. (Round your answer to 2 decimal places.) Reject H0 if F> d-2. What is the computed value of F? (Round your answer to 1 decimal place.) Value of F d-3. Determine whether any of the regression coefficients are significant. ----------------Reject H0 Atleast One regression Coefficient is---------------- Accept Zero…arrow_forwardIn order to determine a realistic price for a new product that a company wants to market the company’s research department selected 10 sites thought to have essentially identical sales potential and offered the product in each at a different price. The resulting sales are recorded in the accompanying table: Price ($) Sales ($1,000s) 15.00 15 15.50 14 16.00 16 16.50 9 17.00 12 17.50 10 18.00 8 18.50 9 19.00 6 19.50 5 c). Find the equation of the sample regression line using Minitab. d). Interpret the meaning of the coefficients of the equation of the sample regression line.arrow_forwardA researcher developed a regression model to predict the cost of a meal based on the summated rating (sum of ratings for food, decor,and service) and the cost per meal for 12 restaurants. The results of the study show that b1=1.4379 and Sb1=0.1397. a. At the 0.05 level of significance, is there evidence of a linear relationship between the summated rating of a restaurant and the cost of a meal? b. Construct a 95% confidence interval estimate of the population slope, β1. a. Determine the hypotheses for the test. Choose the correct answer below. A. H0: β1=0 H1: β1≠0 B. H0: β0≤0 H1: β0>0 C. H0: β1≤0 H1: β1>0 D. H0: β0≥0 H1: β0<0 E. H0: β1≥0 H1: β1<0 F. H0: β0=0 H1: β0≠0 Compute the test statistic. The test statistic is ? (Round to two decimal places as needed.) Determine the critical value(s). The critical value(s) is(are) ? (Use a comma to separate answers as needed.…arrow_forward
- A linear regression model was fit to a set of data containing 18 observations. The computer output of the regression analysis is shown in the table. Term CoefCoef SE CoefSE Coef TT Constant 12.00 5.43 2.210 xx 0.694 0.241 2.880 Assume the conditions for regression are met. Which of the following defines the margin of error when a 95 percent confidence interval for the slope of the least-squares regression line is calculated? (1.75)(0.241) A (1.75)(0.694) B (1.96)(0.241) C (2.12)(0.241)) D (2.12)(0.694) Earrow_forwardThe following data are from a random sample of 10 students who participated in a study undertaken to investigate the effect of sleep time (measured in average number of hours of sleep per night) on GPA (grade point average, measured on a 4-point scale). Student Sleep time GPA 1 7 3.28 2 9 3.16 3 8 3.75 4 6 2.50 5 4 2.45 6 8 2.91 7 7 3.53 8 6 3.02 9 3 2.30 10 8 3.48 a. Find the equation between GPA (y) as function of sleep time (x). b. What is the estimated GPA of a student who averages 5 hours of sleep per night? c. What is the coefficient of determination? *(no use EXCEL)arrow_forwardAn article in Knee Surgery, Sports Traumatology, Arthroscopy (2005, Vol. 13, pp. 273-279) considered arthroscopic meniscal repair with an absorbable screw. Results showed that for tears greater than 25 millimeters, 14 of 18 (78%) repairs were successful, but for shorter tears, 22 of 30 (73%) repairs were successful. A doctor would like to know if there is evidence that the success rate is greater for longer tears. The P-value for the test H0: p1 = p2 versus H1: p1 > p2 is closest to:arrow_forward
- From the below table, Use excels to find the answer for the below questions: State Percentage Proficient in Reading Percentage Proficient in Mathematics California 60 59 Texas 73 78 New York 75 70 Florida 66 68 Illinois 75 70 Pennsylvania 79 77 Ohio 79 76 Michigan 73 66 Georgia 67 64 North Carolina 71 73 Activities: Compute the least-squares regression line for predicting math proficiency from reading proficiency. Interpretation of the least-squares regression line in part a.arrow_forwardThe table below shows the numbers of bushels of barley cultivated per acre for 12 one-acre plots of land for two different strains of barley, PHT-34 and CBX-21. PHT-34 CBX-21 43 55 49 46 47 43 38 44 47 45 45 49 50 47 46 59 46 52 46 49 45 48 43 51 Determine the minimum data value, the quartiles, and the maximum data value for the PHT-34 and CBX-21 data sets. PHT-34 CBX-21 min Q1 Q2 Q3 maxarrow_forwardWhich regressors are meaningful at the 5% significance level according to the Minitab output given below for regression analysis? (n=12) A)Only x3 B)Only x1 C)x2 and x3 D)x1 and x2arrow_forward
- Following are the protein contents measured in two types of species:Species 1: 0.72 1.12 0.81 0.89 0.72 0.81 1.01 0.75 0.83Species 2: 1.21 0.93 0.80 1.12 1.22 0.94 0.87 i) Assuming normality, test the hypothesis that the two species have the sameaverage protein contents by using 5-step hypothesis testing procedure at 5 %level of significance, and using the critical values approach.ii) Calculate the p-value of this test and make decision.iii) Write down the standard error of this test and calculate its numerical value ?arrow_forwardConsider a cohort study to compare the mortality rate of myocardial infarction (MI) in men with sedentary work (exposed group) to men with physically active work (unexposed). If in the exposed, there were 36,000 person (man) years of observation and 126 deaths whereas the unexposed had 24,000 man-years of observation and 44 deaths. Compute the following a) Mortality rate in each cohort? b) What is the relative risk of dying, comparing these 2 groups? c) What is the attributable risk of sedentary work? d) What is the attributable benefit of physical activity? e) If we assume that MI is associated with the mortality in this cohort (causality), what proportion of the disease in the higher group is potentially preventable?arrow_forwardWhich of the independent variables retains the strongest association with the number of children a respondent has when all other variables in the model are controlled?arrow_forward
arrow_back_ios
SEE MORE QUESTIONS
arrow_forward_ios
Recommended textbooks for you
- MATLAB: An Introduction with ApplicationsStatisticsISBN:9781119256830Author:Amos GilatPublisher:John Wiley & Sons IncProbability and Statistics for Engineering and th...StatisticsISBN:9781305251809Author:Jay L. DevorePublisher:Cengage LearningStatistics for The Behavioral Sciences (MindTap C...StatisticsISBN:9781305504912Author:Frederick J Gravetter, Larry B. WallnauPublisher:Cengage Learning
- Elementary Statistics: Picturing the World (7th E...StatisticsISBN:9780134683416Author:Ron Larson, Betsy FarberPublisher:PEARSONThe Basic Practice of StatisticsStatisticsISBN:9781319042578Author:David S. Moore, William I. Notz, Michael A. FlignerPublisher:W. H. FreemanIntroduction to the Practice of StatisticsStatisticsISBN:9781319013387Author:David S. Moore, George P. McCabe, Bruce A. CraigPublisher:W. H. Freeman
MATLAB: An Introduction with Applications
Statistics
ISBN:9781119256830
Author:Amos Gilat
Publisher:John Wiley & Sons Inc
Probability and Statistics for Engineering and th...
Statistics
ISBN:9781305251809
Author:Jay L. Devore
Publisher:Cengage Learning
Statistics for The Behavioral Sciences (MindTap C...
Statistics
ISBN:9781305504912
Author:Frederick J Gravetter, Larry B. Wallnau
Publisher:Cengage Learning
Elementary Statistics: Picturing the World (7th E...
Statistics
ISBN:9780134683416
Author:Ron Larson, Betsy Farber
Publisher:PEARSON
The Basic Practice of Statistics
Statistics
ISBN:9781319042578
Author:David S. Moore, William I. Notz, Michael A. Fligner
Publisher:W. H. Freeman
Introduction to the Practice of Statistics
Statistics
ISBN:9781319013387
Author:David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:W. H. Freeman
Correlation Vs Regression: Difference Between them with definition & Comparison Chart; Author: Key Differences;https://www.youtube.com/watch?v=Ou2QGSJVd0U;License: Standard YouTube License, CC-BY
Correlation and Regression: Concepts with Illustrative examples; Author: LEARN & APPLY : Lean and Six Sigma;https://www.youtube.com/watch?v=xTpHD5WLuoA;License: Standard YouTube License, CC-BY