NAME:       Electric Bill Data	

TYPE:       Sample	

SIZE:       120 observations, 13 variables 	
		
DESCRIPTIVE ABSTRACT:		
The dollar amount for a monthly (January 1991 through December 2000) 
household electric bill is presented as a time series. In addition, 
potential explanatory variables are included. Twelve representative 
monthly values are provided for the average temperature, for 
heating degree days, and for cooling degree days (not for each 
month for each year). Additional variables give the family size 
each month and indicate when a new electric meter and new heating 
and cooling equipment was installed. To convert the billing amount 
to estimated power consumption, a tiered rate function (supplied 
in the accompanying Instructor's Manual) and the costs of 
associated riders (provided here) must be used. Consumption 
estimates resulting from this information are supplied.	
		
SOURCES:		
Personal data records were used for the actual billing amount and 
other household variables. Temperature and heating and cooling 
degree days can be retrieved from NOAA sites such as 
http://lwf.ncdc.noaa.gov/oa/documentlibrary/hcs/hcs.html. Heating 
and cooling degree days computation methods were revised in July 
2002.

DATASET LAYOUT:

 Column  Description                                   Label
 1 -  3  Observation number                            NUM
 5 -  8  Year                                          YEAR
10 - 12  Month                                         MONTH
14 - 19  Amount of bill (in dollars),                  BILL
           includes 5% sales tax 
21 - 24  Average temperature (in degrees Fahrenheit)   TEMP
26 - 29  Heating Degree Days                           HDD
31 - 33  Cooling Degree Days                           CDD
35       Number of family members at home              SIZE
37       New meter? (indicator variable, 1 = yes)      METER
39       New heat pump 1? (indicator variable, 1= new) PUMP1
41       New heat pump 2? (indicator variable, 1= new) PUMP2
43 - 52  Total charge (per kwh) for all riders         RIDER TOTAL
54 - 58  Calculated consumption (in kwh)               CONSUMPTION

The dataset contains values for January 1991 through December 2000. 
The values are aligned and delimited by spaces. Missing values are 
denoted by "*."

SPECIAL NOTES: 
The entry for the BILL in January 1994 is missing. The entry of $0.00 
for August 1999 is correct. This value prompted the power company to 
replace the electric meter.

Heating Degree Days is defined as the cumulative number of degrees in 
a month by which the mean temperature falls below 65 degrees. These 
values are thirty-year averages for this geographic location.

Cooling Degree Days is defined as the cumulative number of degrees in 
a month by which the mean temperature rises above 65 degrees. These 
values are thirty-year averages for this geographic location.

Twelve values are provided for Average Temperature, Heating Degree Days, 
and Cooling Degree Days. These values repeat over the course of the 
time series.

PEDAGOGICAL NOTES
These data are appropriate to use in statistics classes at a variety 
of levels. Using only the billing amounts, the data provide a time 
series for students to examine visually for seasonal patterns and 
trend. Analysis could lead to the discussion of the treatment of 
missing values and outliers, but if this is beyond the scope of the 
course, the instructor could certainly adjust the values for those 
periods prior to giving the data to the students. This time series 
is quite effective for teaching seasonal decomposition and other 
forecasting techniques. When additional variables are incorporated, 
it is a good application for multiple regression. The data can also 
be used for spreadsheet exercises.

SUBMITTED BY:
Constance McLaren
Analytical Department
Indiana State University
Terre Haute, IN 47809
USA
c-mclaren@indstate.edu

Bruce McLaren
Organizational Department
Indiana State University
Terre Haute, IN 47809
USA
b-mclaren@indstate.edu

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