PSYC 3000 Midterm: midterm cheat.docx
21 Mar 2012
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Document Summary
Run-series plots: horizontal axis=time/sequence, vertical= value of each observation (detect sudden changes, gradual change/trend, patterns, problems, changes in variance, plotted same sequence as gathered, shows all data) Scatter plots: show all data points, 2 variables on 2 axes, reveals unusual relationships btw variables, detect changes in experimental conditions. Histograms: not show all data points, just summary. Atleast interval data on x-axis, y axis starts at 0. Numeric tools: symmetric and no severe outliers= mean and sd. Not symmetric= median and semi-interquartile range (resistant to outliers and can be used for ordinal). Mean= average, interval/ratio, easy but affected by outliers, Median=ordinal but not for anova, mode=nominal, most frequent, affected by sampling fluctuations. Standard deviation=square root of variance (affected by extreme scores but easy for. Interquartile range= q3-q1/2 (resistant to outliers but not sampling fluctuations). Boxplots=summary of data, 50% data in box, 99% inside fences, dispersion. symmetry/outliers, compare distributions/ medians.
