PNB 3RM3 Lecture Notes - Lecture 2: Central Limit Theorem, Insomnia, Scatter Plot
5 Oct 2020
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A variable is something that varies: ex: shoe size, levels of depression, number of hours slept, etc. Variables can be: quantitative (ex: height, categorical (ex: employment status) Variables must be operationally defined (ex: how will you measure your variable exactly?) You have to define what your variable will me. Population: the group which we try to draw conclusions on. Sample: a subset of the population that is studied. Samples are often defined by availability more than representativeness. Two basic types of sr"s: (1) correlations, (2) differences between groups, correlations: Do correlations when you have two variables on a continuous scale and want to see the relationship between these variables. Examines the relationship between two variables e. g. , depression and hours of sleep: represented by a scatterplot. Correlation does not have a manipulated variable e. g. , researcher measures numbers of hours people sleep and their levels of depression. But ideally, you show more info than just the mean.
