Accessing the data set by:

install.packages("faraway")

library(faraway)

data(aatemp)

in r studio.

Problem 2 The aa'temp data in the faraway library comes from the US. Historical Climatological Network. The data report annual mean temperatures in Ann Arbor Michigan for roughly 150 years. 3) Fit a linear trend model to temperature as a function of year and display the model summary. Does there appear to be a trend? Answer: b) For the model in a), plot residuals versus year, connecting the dots in the plot (type= ' o ' ), and adding a horizontal reference line at U. Is there any evidence of serial correlation in the graph? Answer: c) Based on the model in a), test for serial correlation between successive years using the Durbin-Watson test, and state your conclusion. Answer: {1} Using the gls function from the nlme library, t a linear trend model using the ARI harm of correlation between years. Display the model summary. Does the trend line change much? HOW much correlation is there, based on the estimated ARI correlation parameter? Answer: e) Again using the gls function, t a cubic model (third order polynomial) for temperature as a function of year, with the ARI form of correlation. Display the model summary. Males a scatter plot of temp versus year, and add the tted curves from the linear and 3rd order polynomial models to the graph. One way to do this is with lines command after creating the plot, e.g. lines (mod$fi1:ted~year, data=aatemp). 1Which model seems to track the data better, based on what you see