2 1.2: Data Classification Variables can be classified in two ways: Qualitative Variable– variables that can be placed into distinct categories, according to some characteristic or attribute.Quantitative Variable– variables that are numerical and can be ordered or ranked.
3 Quantitative Variables Section 1.2Quantitative VariablesThere are two types of quantitative variables:Discrete Variables – can be assigned values such as 0, 1, 2, 3. Variables are able to be counted.Continuous Variables – can assume an infinite number of values between any two specific values. Values are obtained by measuring (often include decimals and fractions).
4 The classification of variables can be summarized as follows: Section 1.2The classification of variables can be summarized as follows:DataQualitativeQuantitativeDiscreteContinuous
5 Section 1.2 Measurement Scales Nominal – classifies data using names, labels, or qualities.Mutually exclusive (non-overlapping)Exhausting categories (not infinite)No order or ranking can be imposed on the data.Lowest level of measurement.Qualitative data only.Examples: eye color, political party, zip code
6 Section 1.2 Measurement Scales Ordinal – classifies data into categories that can be ranked.Precise differences between the ranks are not meaningful.Second lowest level of measurementCan be qualitative or quantitative.Examples: letter grades, Olympic medals
7 Section 1.2 Measurement Scales Interval – classifies data into categories that can be ranked and have precise differences.There is no meaningful zero (the number zero represents a position on the scale).Second highest level of measurementExamples: temperature, money in a savings account
8 Section 1.2 Measurement Scales Ratio - possesses all the characteristics of interval measurement and there exists a true zero.Highest level of measurementExamples: height, weight, time
9 Homework Page 13: Nominal, Ordinal Ordinal, Interval, Ratio False: Data at the ordinal level can be qualitative or quantitative.False: For data at the ordinal level, you cannot calculate meaningful differences between data entries.False: Less types of calculations can be performed with data at the nominal level than with data at the interval level.False: Data at the ratio level can be put in order.