Variables

Numerical Variable (Quantitative Data)

• Take numerical values

Discrete Variables

• Quantitative variables that can take only a limited number of values

• Ordering and magnitude are important

• Fix amount that is a whole number

  • Ex: Number of motor vehicles accidents in georgia in a specific month (cannot have half of a crash)

Continuous Variables

• Any real numerical value over an interval

• Sometimes continous data is rounded

  • Measureable quantities that are not restricted to certain values

  • Fractions and decimals are possible

• Rule of thumb: if you could take on a value between any two other numbers

• Ex: blood pressure in mmHg, age, weight in pounds

Categorical Variable (Qualitative Data)

• Places individual into one of several groups or categories (Qualitative or Characteristic)

Nominal Variable

• Purely qualitative and unordered

• Numbers often represent categories

  • number is unimportant, just a label

• Ex: 1 = black, 2 = brown, 3 = blonde, 4 = red

Dichotomous or Binary Variable

• Nominal variables that take on one of two possible distinct values

• Ex: Gender: 0 = Male, 1 = Female

Ordinal Variable

• Qualitative and ordered (hierarchy)

• Numbers are used to represent categories

  • Ex: Stages of ovarian cancer, letter grade, likert scales

Likert Scales- Widely used in survey research

• Ex: On a scale of 1-10, how much does it hurt?