Lecture 1 Show
Discrete and continuous variables Levels of measurement Nominal Ordinal Interval Ratio One can think of nominal, ordinal, interval, and ratio as being ranked in their relation to one another. Ratio is more sophisticated than interval, interval is more sophisticated than ordinal, and ordinal is more sophisticated than nominal. I don't know if the ranks are equidistant or not, probably not. So what kind of measurement level is this ranking of measurement levels?? I'd say ordinal. In statistics, it's best to be a little conservative when in doubt. Two General Classes of Variables (Who Cares?) Ordinal scales with few categories (2,3, or possibly 4) and nominal measures are often classified as categorical and are analyzed using binomial class of statistical tests, whereas ordinal scales with many categories (5 or more), interval, and ratio, are usually analyzed with the normal theory class of statistical tests.� Although the distinction is a somewhat fuzzy one, it is often a very useful distinction for choosing the correct statistical test.� There are a number of special statistics that have been developed to deal with ordinal variables with just a few possible values, but we are not going to cover them in this class (see Agresti, 1984, 1990; O�Connell, 2006; Wickens, 1989 for more information on analysis of ordinal variables). General Classes of Statistics (Oh, I Guess I Do Care)
Survey Questions and Measures: Some Common Examples Yes/No Questions Likert Scales Physical Measures Counts How do you know if data is nominal ordinal interval or ratio?Nominal: the data can only be categorized. Ordinal: the data can be categorized and ranked. Interval: the data can be categorized and ranked, and evenly spaced. Ratio: the data can be categorized, ranked, evenly spaced and has a natural zero.
When the data are labels or names used to identify an attribute of the elements and the rank of the data is meaningful the variable has which scale of measurement?
Are labels used to identify attributes of elements?Labels or names used to identify an attribute of each element. Categorical data use either the nominal or ordinal scale of measurement and may be nonnumeric or numeric. Numeric values that indicate how much or how many of something. Quantitive data are obtained using either the interval or ratio scale of measurement.
What is nominal and ordinal scale?Nominal scale is a naming scale, where variables are simply “named” or labeled, with no specific order. Ordinal scale has all its variables in a specific order, beyond just naming them. Interval scale offers labels, order, as well as, a specific interval between each of its variable options.
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