01 STAT intro-SD S14 all(2)

# Examples xnumberofchildren xnumberofnewpatents

This preview shows page 1. Sign up to view the full content.

This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: bles • Often categorical variables are coded with numbers • Look like numerical variables but really are NOT – really important! 16 NUMERICAL VARIABLES Numerical variables can be either discrete or continuous or approximately continuous Definition A discrete variable is one where we can count the number of possible values of the variable. Examples: X = number of children X = number of new patents (sample of families) (sample of annual data for chemical companies) Other discrete variables? 17 NUMERICAL VARIABLES Definition A continuous variable is one that can take on any value in a continuum—any value on the real line, or in an interval of the real line. Examples X = wind speed (sample of daily data for several locations near wind farms) X = hours to assemble/finish a vehicle (sample of vehicles from assembly lines) X = emissions (sample of monthly data for factories) Other continuous variables Probability models for discrete and continuous variables are fundamentally different. 18 NUMERICAL VARIABLES A discrete variable can be treated (modeled) as continuous, and is said to be approximately continuous, if the following conditions are met: 1) the unit of measurement is small compared to the typical value of variable (or the range of values of the variable) 2) the number o...
View Full Document

{[ snackBarMessage ]}

Ask a homework question - tutors are online