Average monthly temperatures. Here are the average monthly temperatures for Chicago, Illinois:
In this table, months are coded as integers, with January corresponding to 1 and December corresponding to 12.
(a) Plot the data with month on the x axis and temperature on the y axis. Describe the relationship.
(b) Find the least-squares regression line and add it to the plot. Does the line give a good fit to the data? Explain your answer.
(c) Calculate the residuals and plot them versus month. Describe the pattern and explain what the residual plot tells you about the relationship between temperature and month in Chicago.
(d) Do you think you would find a similar pattern if you plotted the same kind of data for another city?
(e) Would your answer to part (d) change if the other city was Melbourne, Australia? Explain why or why not.