A different number of lanes was opened each day the

Info icon This preview shows pages 3–4. Sign up to view the full content.

View Full Document Right Arrow Icon
customer to go through the lane and complete the transaction. A different number of lanes was opened each day. The data is below. Date 11/22 11/23 11/29 11/30 12/6 12/7 12/14 12/15 12/21 12/22 12/29 12/30 Weather Sun Cloudy Sun Rain Sun Sun Cloudy Cloudy Cloudy Rain Snow Sun Lanes 5 12 11 7 12 8 6 10 8 6 4 8 Avg Wait Time (Min) 12.2 4.2 4.4 6.75 3.8 5.75 10.4 6.5 6.25 9.2 1.1 5.6 1. What is the explanatory variable? Lanes What is the response variable? Avg wait . 2. For answer # 1, make a scatterplot on your calculator and draw it below. x = lanes, y = avg wait 3. There is a clear outlier on your scatterplot. Circle it. 4. Give a reason that would justify eliminating the outlier. It was snowing. Few customers. 5. Generate the least squares regression line that describes the data (with the outlier eliminated). (2 dec places). ˆ y = " 0.96 x + 14.96 6. Give the meaning of the slope in the LSRL. For every extra lane open, .96 minute less of a wait. 7. What specific point is the LSRL guaranteed to go through? x , y ( ) = 8.45,6.82 ( ) 8. Describe the data in terms of form, direction, and strength. Fairly strong negative linear correlation 9. Find the value of r . r = " .88. Interpret it. Fairly strong negative linear correlation 10. Find the value of r 2 = .78. Interpret it. 78% of the variation in waiting time can be explained by the LSRL. 11. What is the predicted average waiting time if Walmart opens 9 lanes? 6.32 minutes 12. What is the predicted average waiting time if Walmart opens 7 lanes? 8.24 minutes 13. What is the difference between the actual waiting time and predicted waiting time for 7 lanes? " 1.5 min 14. If Walmart decides that it wants its customers to wait no longer than 4.5 minutes, how many lanes should it open? 11 lanes. 15. If Walmart decides that it wants its customers to wait no longer than 10 minutes, how many lanes should it open? 6 lanes 16. What is the predicted average waiting time if Walmart opens only one lane? 14 min. 17. What is the predicted average waiting time if Walmart opens 20 lanes? -4.24 min 18. Why do the last two problems and answers make little sense for this problem? Extrapolation is always dangerous. The minimum waiting time must be positive.
Image of page 3

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document Right Arrow Icon
Stu Schwartz On the same days of the previous problem, Walmart will need to hire extra staff to man the checkout lanes. They will have to pay out more money for the workers. The chart below describes how much money in pay it paid out during those hours on these specific days.
Image of page 4
This is the end of the preview. Sign up to access the rest of the document.

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern