STAT 2013 Lecture Notes - Lecture 1: Stratified Sampling, Rotten Tomatoes
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Like a line with decimal points, all points and points in between. Points on the number line and just those points: nominal- hair color, can be categorical, ordinal- ordered, ranks of college football teams, rotten tomatoes ranks. Zero does not mean the absence of- like temperature. Zero degrees is not (cid:858) no degrees(cid:859: ratio- natural zero. Zero means absence of- like number of people in a class. Group split up into groups and each person in each group has an equal likely chance of being selected. Ag students and engineering students- random sample from each group. No groups just randomly chosen from the population. Students selected from the university without separating them into majors first. Methods of collecting data: voluntary response- pollsters in commons asking students to participate, internet surveys you can skip over, systematic sampling- selecting ever nth person, convenience- take what is given. A tv station asking people to call in.
