Chapter 1: Intro to Stats & Levels of Measurement

Chapter 1: Intro to Stats & Levels of Measurement New Vocabulary: Categorical variable: a variable that has a finite number of classification groups or categories which are usually qualitative in nature Continuous variable: a variable that has an infinite number of potential values, with the value being measured falling somewhere on a continuum containing in-between values Independent variable: the variable being controlled by the experimenter that is thought to cause the outcome Dependent variable: the outcome variable that is the final result Quantitative: a numerical variable Qualitative: a measure that describes or characterizes an attribute Population vs. Sample -​ A sample is a subset of a population or group -​ Population refers to the entire group or focus of the study Quantitative vs. Qualitative -​ The independent variable impacts/changes the dependent variable -​ Eg. Does having family support (independent variable) affect the duration of a hospital stay (dependent variable) Continuous vs. Categorical -​ Continuous variables are on a continuum with in-between values such as height, weight, and temperature -​ Categorical variables are discrete, and have a finite number of groups or categories (such as what gender you are, or nationality) Levels of Measurement “NOIR” -​ Nominal - categories without any implied ordering (eye colour, gender, marital status) -​ Ordinal - has categories that can be ordered (pain scale, years of study) -​ Interval - has categories, has order, order is evenly spaced, but there is no absolute zero (temperature, IQ scores) -​ No absolute zero means you can have negative values -​ Ratio - has categories, has order, order is evenly spaces, but has absolute zero (height, weight) -​ Absolute zero means that you cannot have values below zero