Does the OTR time appear to be stable? , Business statistic homework help

Does the OTR time appear to be stable? , Business statistic homework help

Use the date in table above and answer the following questions in the space provided below:

  1. Does the OTR time appear to be stable?  Why or why not?
  2. If you were to use a control chart to evaluate stability, which chart would you use?  Why?
  3. What can you learn about the distribution of the installation process? 
  4. Does it appear that the country has an impact on installation time? Why or why not?