Story Name: US Temperatures

Abstract: The data gives the normal average January minimum temperature in
degrees Fahrenheit with the latitude and longitude of 56 U.S. cities. (For each
year from 1931 to 1960, the daily minimum temperatures in January were added
together and divided by 31. Then, the averages for each year were averaged over
the 30 years.)


Show that there is a strong association between latitude and temperature except
for the coasts where the ocean has a moderating effect on the temperature.

Show that both latitude and longitude are significant predictors of JanTemp.

Show that the relationship between JanTemp and Lat, after removing the effects of
Long, is linear and negative.

Show that the relationship between JanTemp and Long, after removing the effects
of Lat, is not linear.


Peixoto (1990) reports a study in which a linear relationship is assumed between
JanTemp and Lat; then, after removing the effects of Lat, a cubic polynomial in
Long is used to predict JanTemp.

Reference: Peixoto, J.L. (1990) A property of well-formulated polynomial
regression models. American Statistician, 44, 26-30. Also found in: Hand, D.J.,
et al. (1994) A Handbook of Small Data Sets, London: Chapman & Hall, 208-210.
Authorization: Free Use Description: The data gives the normal average January
minimum temperature in degrees Fahrenheit with the latitude and longitude of 56
U.S. cities. (For each year from 1931 to 1960, the daily minimum temperatures in
January were added together and divided by 31. Then, the averages for each year
were averaged over the 30 years.) Number of cases: 56 Variable Names:

1.City: City, State postal abbreviation
2.JanTemp: Average January minimum temperature in degrees F. from 1931-1960
3.Lat: Latitude in degrees north of the equator
4.Long: Longitude in degrees west of the prime meridian

The Data:

City JanTemp Lat Long
Mobile, AL 44 31.2 88.5
Montgomery, AL 38 32.9 86.8
Phoenix, AZ 35 33.6 112.5
Little Rock, AR 31 35.4 92.8
Los Angeles, CA 47 34.3 118.7
San Francisco, CA 42 38.4 123.0
Denver, CO 15 40.7 105.3
New Haven, CT 22 41.7 73.4
Wilmington, DE 26 40.5 76.3
Washington, DC 30 39.7 77.5
Jacksonville, FL 45 31.0 82.3
Key West, FL 65 25.0 82.0
Miami, FL 58 26.3 80.7
Atlanta, GA 37 33.9 85.0
Boise, ID 22 43.7 117.1
Chicago, IL 19 42.3 88.0
Indianapolis, IN 21 39.8 86.9
Des Moines, IA 11 41.8 93.6
Wichita, KS 22 38.1 97.6
Louisville, KY 27 39.0 86.5
New Orleans, LA 45 30.8 90.2
Portland, ME 12 44.2 70.5
Baltimore, MD 25 39.7 77.3
Boston, MA 23 42.7 71.4
Detroit, MI 21 43.1 83.9
Minneapolis, MN 2 45.9 93.9
St. Louis, MO 24 39.3 90.5
Helena, MT 8 47.1 112.4
Omaha, NE 13 41.9 96.1
Concord, NH 11 43.5 71.9
Atlantic City, NJ 27 39.8 75.3
Albuquerque, NM 24 35.1 106.7
Albany, NY 14 42.6 73.7
New York, NY 27 40.8 74.6
Charlotte, NC 34 35.9 81.5
Raleigh, NC 31 36.4 78.9
Bismarck, ND 0 47.1 101.0
Cincinnati, OH 26 39.2 85.0
Cleveland, OH 21 42.3 82.5
Oklahoma City, OK 28 35.9 97.5
Portland, OR 33 45.6 123.2
Harrisburg, PA 24 40.9 77.8
Philadelphia, PA 24 40.9 75.5
Charleston, SC 38 33.3 80.8
Nashville, TN 31 36.7 87.6
Amarillo, TX 24 35.6 101.9
Galveston, TX 49 29.4 95.5
Houston, TX 44 30.1 95.9
Salt Lake City, UT 18 41.1 112.3
Burlington, VT 7 45.0 73.9
Norfolk, VA 32 37.0 76.6
Seattle, WA 33 48.1 122.5
Spokane, WA 19 48.1 117.9
Madison, WI 9 43.4 90.2
Milwaukee, WI 13 43.3 88.1
Cheyenne, WY 14 41.2 104.9