Statistical Sciences 1024A/B Lecture Notes - Lecture 8: Word Problem For Groups, Block Design, Big Difference
30 Sep 2015
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Observational study-observes individuals & measures variables of interest. There"s no attempt to influence responses (sampling surveys are one kind of observational study) Experiment- deliberately imposes some treatment on individuals in order to observe their response. The inside workers were mostly female. the outside workers were all male. You can address the problems of confounding variables with well designed experiments. Sampling population versus samples: population is the entire group of individuals that we want information about, whereas the sample is part of the population examined in order to gather information. Purpose of samples is to use sample to draw conclusions about the population. Types of sampling & bias: voluntary response samples: those who choose to respond themselves by responding to a general appeal. ann landers example: judgment samples: those whom the person doing the sampling thinks best represents the population. mkt research quota sample: convenience samples: consists of those easiest to reach.
