Assignment

Use Minitab/file attached:

The time to download files primarily depends on the size of the file. A manager asked to determine what, if any, relationship exists between download time and size of file. The manager randomly selected a sample and provided the information in the file Download Time (attached). (Questions a-i)

a. develop a scatter plot of the data. IS there a relationship between the two variables? What kind?

b. Use the simple linear regression to predict the download time if the size of a file is 7.0

c. conduct a test, using an alpha value of 0.5, to determine whether or not  if increasing the file size results in increases of download time.

d. Set up a 90% confidence interval estimate for download time if the file size was equal to 7.0.

e. using appropriate plots determine whether any of the regression assumptions have been violated (residual analysis)

f. Using the data file, now develop a nonlinear model and plot the model against the data. Using an alpha of 0.5. Is this model good for predicting download time?

g. Using appropriate plots determine whether any of the regression assumptions have been violated (residual analysis).

h. Does the nonlinear model provide a better fit than the linear model previously developed? (Use a statistical test).

i. Set up a 90% confidence interval estimate for download time if the file size was equal to 7.0 using the nonlinear model.