2. A large industrial plant has six divisions that do the same type of work. A safety inspector visits each division of 20 workers quarterly. The number of work-hours devoted to safety training and the number of work-hours lost due to industry-related accidents for the seven divisions are recorded below. Let x represent the number of work-hours in safety training and let y represent the number of work-hours lost due to accidents. Work hours in safety training (x) Work-hours lost due to accidents (v) Suppose x = 45, s, = 24.9, y = 44.2, s, = 22.2 a. Make a scatterplot for the data. b. Use the mean and standard deviation information provided to calculate the correlation coefficient, r, between the two variables. Show work. Round to two decimal places. c. Based on your answer to part b., do you think the points lie close to a straight line? Explain. d. Based on your answer to part b., describe the association between the two variables. Explain. Your work in part b should indicate that r=-.91 Use this value for r and the other information provided to find the equation of the least squares regression line (round a and b to the nearest whole number). e. f. What is the slope of the regression line? Explain its meaning relative to this problem situation. g. What is the y-intercept of the regression line? Is it meaningful in this situation? Explain. h. List 2 points that you know will be on the least-squares line you found in part a. 10 75 20 45 60 65 70 55 60 30 20 25 i. Graph the least-squares line on your scatterplot from part a. J. What percent of variation is accounted for by a linear relationship? k. Use the equation of the least-squares regression line to predict the number of work-hours lost due to accidents for a person who spends 30 work-hours in safety training. 1. Would it make sense to use the least-squares line to predict the work-hours lost due to accidents for a person who spends 150 work-hours in safety training? Explain using any appropriate terms.
2. A large industrial plant has six divisions that do the same type of work. A safety inspector visits each division of 20 workers quarterly. The number of work-hours devoted to safety training and the number of work-hours lost due to industry-related accidents for the seven divisions are recorded below. Let x represent the number of work-hours in safety training and let y represent the number of work-hours lost due to accidents. Work hours in safety training (x) Work-hours lost due to accidents (v) Suppose x = 45, s, = 24.9, y = 44.2, s, = 22.2 a. Make a scatterplot for the data. b. Use the mean and standard deviation information provided to calculate the correlation coefficient, r, between the two variables. Show work. Round to two decimal places. c. Based on your answer to part b., do you think the points lie close to a straight line? Explain. d. Based on your answer to part b., describe the association between the two variables. Explain. Your work in part b should indicate that r=-.91 Use this value for r and the other information provided to find the equation of the least squares regression line (round a and b to the nearest whole number). e. f. What is the slope of the regression line? Explain its meaning relative to this problem situation. g. What is the y-intercept of the regression line? Is it meaningful in this situation? Explain. h. List 2 points that you know will be on the least-squares line you found in part a. 10 75 20 45 60 65 70 55 60 30 20 25 i. Graph the least-squares line on your scatterplot from part a. J. What percent of variation is accounted for by a linear relationship? k. Use the equation of the least-squares regression line to predict the number of work-hours lost due to accidents for a person who spends 30 work-hours in safety training. 1. Would it make sense to use the least-squares line to predict the work-hours lost due to accidents for a person who spends 150 work-hours in safety training? Explain using any appropriate terms.
MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
Related questions
Question
Transcribed Image Text:2. A large industrial plant has six divisions that do the same type of work. A safety inspector visits each
division of 20 workers quarterly. The number of work-hours devoted to safety training and the number
of work-hours lost due to industry-related accidents for the seven divisions are recorded below. Let x
represent the number of work-hours in safety training and let y represent the number of work-hours lost
due to accidents.
Work hours in safety training (x)
Work-hours lost due to accidents (y) 75
Suppose x = 45, s, = 24.9, y = 44.2, s, = 22.2
a. Make a scatterplot for the data.
b.
c.
d.
e.
f.
g.
h.
10 20 45 60 65 70
55
30 20 25
60
Use the mean and standard deviation information provided to calculate the correlation
coefficient, r, between the two variables. Show work. Round to two decimal places.
Based on your answer to part b., do you think the points lie close to a straight line? Explain.
Based on your answer to part b., describe the association between the two variables. Explain.
Your work in part b should indicate that r=-.91 Use this value for r and the other
information provided to find the equation of the least squares regression line (round a and b to
the nearest whole number).
What is the slope of the regression line? Explain its meaning relative to this problem situation.
What is the y-intercept of the regression line? Is it meaningful in this situation? Explain.
List 2 points that you know will be on the least-squares line you found in part a.
i. Graph the least-squares line on your scatterplot from part a.
j. What percent of variation is accounted for by a linear relationship?
k. Use the equation of the least-squares regression line to predict the number of work-hours lost
due to accidents for a person who spends 30 work-hours in safety training.
1.
Would it make sense to use the least-squares line to predict the work-hours lost due to accidents
for a person who spends 150 work-hours in safety training? Explain using any appropriate
terms.
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