PSYCH 2220 Lecture 5: Chapter 5 - Sampling & Probability
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We have to estimate the likelihood that our sample resembles the pop. Every member of pop of interest has equal chance of being selected into study. Convenience samples decreased generalizability (external validity) Volunteer samples = even more concern about bias. All participants have equal chance of being assigned to any level of iv. Be careful of confirmation bias when viewing coincidence. Paying attention to confirming evidence, ignoring disconfirming evidence. Draw one out, note color, replace - do it a lot of times. Each occasion a procedure is carried out. E. g. every time i draw out an m&m. Believing there is an association b/t 2 events when there is not. Laura sent a balloon up, and another laura buxton found it. Probability is a rating of our confidence that this event will occur. Outcome we wish to know the probability of. The outcome of one trial has no effect on the outcome of another trial.