Question: Winter in the city. Summary statistics for the data relating the latitude and average January temperature for 55 large U.S. cities are given below.

Variable         Mean        StdDev

Latitude        39.02          5.42

JanTemp       26.44         13.49

      Correlation = -0.848

a) What percent of the variation in January Temperatures can be explained by variation in Latitude?

b) What is indicated by the fact that the correlation is negative?

c) Write the equation of the line of regression for predicting January Temperature from Latitude.

d) Explain what the slope of the line means.

e) Do you think the y-intercept is meaningful? Explain.

f) The latitude of Denver is . Predict the mean January temperature there.

g) What does it mean if the residual for a city is positive?