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
|
|
Jan Temp
|
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 of the line is meaningful? Explain.
f) The latitude of Denver is 40° N. Predict the mean January temperature there.
g) If the residual for a city is positive, what does that mean?