Data Sample

# The NY Dairy Herd Improvement Cooperative in Upstate New York (NYDHIC) collects and analyzes data on milk production. One question of interest here is how to develop a suitable model to predict current milk production from a set of measured variables.

# The response variable (current milk production in pounds) and the predictor variables are given in Table below (Data Variable Definitions). Samples are taken once a month during milking. The period that a cow gives milk is called lactation. Number of lactations is the number of times a cow has calved or given milk.

# The recommended management practice is to have the cow produce milk for about 305 days and then allow a 60-day rest period before beginning the next lactation.

# The data set, consisting of 199 observations, was compiled from the NYDHI milk production records.

The Milk Production data can be found on the following Web site:

# http://www.ats.ucla.edu/stat/stata/examples/chp/chpstata_dl.htm
# http://www.ats.ucla.edu/stat/examples/chp/p004.txt

Data Variable Definitions

Variable Definition
Current Current month milk production in pounds
Previous Previous month milk production in pounds
Fat Percent of fat in milk
Protein Percent of protein in milk
Days Number of days since present lactation
Lactation Number of lactations
I79 Indicator variable (0 if Days < 79 and 1 if Days > 79)

 

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