MATH 2233 Lecture Notes - Lecture 2: Frequency Distribution, Frequency (Statistics), Sample Size Determination
16 Nov 2017
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Document Summary
A set of raw data gives us very little information as to how the observations are distributed. For example, consider the following data on caloric intakes of a sample of n = 71 nurses (the data has been ordered from lowest to highest for convenience). Sample range r = h - l = Approximate number of classes: let"s use the root n rule: n = Note that the number of classes is your choice. The root n rule is one of several methods that appear in the literature and is a guideline only. Approximate class width cw = range /(number of classes) = So let"s take a nice round number like cw = 200, and use a convenient number below l as the lower boundary of the first class like 900. Stop when all sample values are included in the classes. [900, 1100), that is the class of values equal to or greater than 900 but below 1100.
