PSYCH 3090 Lecture Notes - Lecture 1: Descriptive Statistics, Psych, Confounding
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All the observations that a researcher is interested in drawing conclusions. A subset of the population: parameter versus statistic, parameter. Example: mean sat score of freshman attending a public university. Normally written using greek letters ( (mu): a group of freshman at usc, and we calculate their mean/average, statistic. Typically written using roman letters (x-bar: descriptive statistics versus inferential statistics, descriptive statistics, inferential statistics. Used to describe the nature of a sample. Uses descriptive statistics to make an inference about what a sample might do: large, random samples yield statistics that better approximate the characteristics of the population compared to other types of samples, example. Independent versus dependent variables: the variable manipulated by a researcher is the independent variable (iv). In our example, we manipulated text messaging: the outcome or the variable that is measured is the dependent variable (dv). In our example we measured the number of lane deviations: iv -> dv, text messaging -> lane deviations.