PS 250 Lecture Notes - Lecture 2: Null Hypothesis
18 Dec 2017
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Document Summary
It is a property which may vary and which its variation is susceptible to be measured. The variable applies to a group of people or objects which can take various values. Variables become of scientific value when they can be related to other values, that is, when they show a relationship. A hypothesis indicates the relationship between two (or more) variables. Ex: the more consumption of alcohol, the higher the probability of car accidents. The assumptions may be true or not, that is why they need to be tested and finally accepted or rejected. Propositions are subject to empirical testing (verification of reality) Not all correlations make sense and form a correlation we cannot always infer causation. In order to establish causation, there must be first a correlation. The cause has to occur before the effect. Changes in the cause must also change effects. H1: sun exposure is linked to skin cancer.
