STATS 250 Study Guide - Midterm Guide: Random Variable, Interquartile Range, Standard Deviation
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STATS 250 Full Course Notes
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An item placed into one of several groups or categories. Typical classroom seat location (front, middle, back), soft drink size (small, medium, large) When the categories have an ordering or ranking. Age (years), number of songs on an ipod, time spent studying (hours) Any value in an interval or collection of intervals. Extraneous variables that correlate to the dependent and independent variables. You want to control for these variables, because they in uence your results. Throughout the year, murder rates and ice cream sales are correlated (they both increase). This is probably not because murders cause people to purchase ice cream or purchasing ice cream cause people to murder, but perhaps because of the weather. When it"s cold, you don"t leave the house to murder people or buy ice cream and when it"s warm, you do. Asking a class of third graders who likes vanilla ice cream (you asked everyone in the class, i. e. the class" population)
