CRM/LAW C167 Lecture Notes - Lecture 2: Law Enforcement Assistance Administration, Quality Assurance, Sampling Error
6 Mar 2016
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Only type we know how to deal with statistically because we can average the random errors and they cancel each other out: validity. Observations: empiricism (core that distinguishes science from an art; logic from mathematics, very crude empirical quantity. Measurement: an observation that we have assigned numbers to, there are three, maybe four measurement scales that we use. Nominal scale = arises whenever we sort (ex. laundry into two piles or three; sort off religion, gender) Assign 0 or 1; we cannot perform basic arithmetic with those numbers. Ordinal scale = set of categories that are exclusive and exhaustive, but that have an ordered property (ex. Rank in the military, class status in college) Interval level measurement = if those ordered categories have a naturally defined unit. Means, averages (an average is a very good prediction) (cid:1) Average crime rate tells us something about our chances of being victimized in a particular city.
