Max January temperature and latitude in US cities
Use this diagram to explain the ideas of fitted values and residuals.
The line is one that might be used to predict temperature from latitude. (It is not the least squares line.) Click any cross to identify the city and display the actual temperature and temperature that is predicted by the line. Its residual is shown in red.
You could mention that positive residuals are above the line and negative ones are below the line.
The data set contains the maximum January temperature (y, in degrees Fahrenheit) and latitude (x, in degrees) of various cities in the USA.
There is one error in the original data set — the latitude for Jacksonville, Florida was incorrectly entered so it appears as an outlier. This will be discussed in a later page.