We will focus on the Extent of the sea ice in this exercise and see how it has

changed over time since $1979.$ Instead of using the actual year as our explanatory

variable, to keep the size of the coefficients manageable, we will use a variable called t$,$

which measures time since $1978($the value for $1979$ is $1).$ Create a residuals versus fits plot for predicting Extent from t$.$ What does this

plot tell you about the idea of fitting a linear model to predict Extent from t$?$

Explain.