PSYC 2001 Lecture Notes - Lecture 9: Standard Deviation, Causal Inference, Internal Validity
15 Dec 2017
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Document Summary
Median: the value at the middlemost score of a distribution of score, dividing the frequency distribution into halves. Variance: a computation that quantifies how spread out the scores of a sample are around their mean; it is the square of the standard deviation. Standard deviation: a computation that captures how far, on average, each score in a data set is from the mean. Z scores: a computation that describes how far an individual score is above or below the mean, in standard deviation units. Significance: a conclusion that a result from a sample is so extreme that the sample is unlikely to have come from a population in which there is no association or no difference. Critical value: a value of a statistic that is associated with a desired alpha level. How to graph categorical vs. quantitative data: categorical: bar graph, quantitative: scatterplot. Measured variable: a variable in an experiment whose values are observed and recorded.
