Fitting a line to data.
******************

With your expertise on making time plots, you will breeze through this exercise.
In the case of time series, you always had a time sequence as  the X-variable
(usually with equally spaced values).  In Chapter 2, you explore the
relationships between all sorts of pairs of quantitative variables.

Once again, the Excel worksheet in the image below contains all the information you need.
 

The data  was loaded from the file F:\PCDataSets\Excel\ CHAP01\ TA01_008.XLS.  

We considered only the data about the 19 two-seater car.   The scatterplot for part a) of Exercise 2.25, and the trend
line are obtained with the usual options.   (For example  See  exercise 1.40.    You DO NOT need to read about the
 "Moving average " option in that exercise ! ).  If you do not want to open exercice 1.40, here are the instructions:

Highlight the cells B2:C20, then click on the Chart icon, choose the "XY-scater" chart type, and click
"Finish".   You should get a chart like the one above, without the trendline and the equation.

Now, to add to the chart a "Trend Line",

Highlight the chart by clicking on it, then click on "Chart" from the menu, and choose "Add trendline " to
open the "Add trendline" window, and then just click OK.
 

  You should get a chart like the one above, without the equation.
 

The other new feature is that now the equation of the fitted line is displayed on the graph.  To do this, you click on the fitted
line and  check that "Option" in the Format Trendline window:
 

Question.  Hand in an Excel worksheet with a chart like  above ,  but having Highway mileages
as the explanatory variable  and City mileages as the response variable .