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Measure Types. Nominal : Unordered Categories Ordinal : Ordered Categories, intervals can’t be assumed to be equal. Interval : Equally spaced categories, 0 is arbitrary and units arbitrary. Ratio : Equally spaced categories, 0 on scale means 0 of underlying quantity. . Measure Type Summary.
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Measure Types • Nominal: Unordered Categories • Ordinal: Ordered Categories, intervals can’t be assumed to be equal. • Interval: Equally spaced categories, 0 is arbitrary and units arbitrary. • Ratio: Equally spaced categories, 0 on scale means 0 of underlying quantity.
Measure Type Summary • Nominal: Unordered Categories
Measure Types • Ordinal: Ordered Categories, intervals can’t be assumed to be equal.
Measure Types • Interval: Equally spaced categories, 0 is arbitrary and units arbitrary.
Measure Types • Ratio: Equally spaced categories, 0 on scale means 0 of underlying quantity.
Measurement Example • 3 students prepared a survey comparing two dishwashing detergents (Sheen and Glitter) on how rough or mild the detergent was on their hands.* • The students developed the following question and scale and administered the survey to 10 respondents for both detergents. The scale used to rate each detergent is below: * This example is adapted from Churchill and Iacobucci (2009)
Measurement Example (2) • The survey responses are listed below:
Measurement Example (3) • Students decided to work individually to code and analyze the responses and then get back together. When they got back together, each of three suggested a different coding scheme. • What is your initial reaction to these scales?
Measurement Example (4) • When the data are coded using each of the three scales, the following mean ratings result (in red below under S and G) . • Any comments or observations?
Measurement Example (5) • The students each calculated the comparative mildness between the detergents as shown below. • What, if any, claims would you make based on the survey? Glitter Sheen * Reverse coded – milder rating is low.
Measurement Example (6) • One final analysis of this question was prepared and is shown below. What does this tell us?
Measurement Example: Summary • Interval Scales: Typically constructed by survey designer • Survey designer controls endpoints, range • Can be coded various ways (linear transformations) • No “natural” zero, so ratios should generally not be used! • Ratio Scales: Typically existent metrics with natural zero (dollars, inches, number of customers) • Survey designer has less choice in specifying response categories • Can consider truncating scale range or transforming data