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The Probability Mass/Density Function (the PMF/PDF): A fancy way of saying ‘what’s the probability of a particular outcome?’ These use the parameters in some expression to yield a value be-tween 0 and 1. We have a PMF if our outcomes are discrete (e.g. the throw of a die), and PDF if it’s continuous (e.g. height). Bernoulli Distribution
S1 Cheat Sheet. You can handily use your calculator’s STAT mode to calculate the mean and variance of a frequency table, find (PMCC) and the and for the line of best fit, along with a number of summations such as Σ , Σ , Σ 2, ... Press SHIFT MODE for setup.
The F statistic is a ratio (a fraction). There are two sets of degrees of freedom; one for the numerator and one for the denominator. For example, if F follows an F distribution and the number of degrees of freedom for the numerator is four, and the number of degrees of freedom for the denominator is ten, then F ~ F 4,10.
Calculating Fisher’s F-ratio is a key step in a number of statistical procedures involving null hypothesis significance testing. This is particularly so in the case of ANOVA (analysis of variance) in its several forms, but even multiple regression includes a test of significance of the overall model which employs an F-ratio.
A random variable has an F distribution if it can be written as a ratio between a Chi-square random variable with degrees of freedom and a Chi-square random variable , independent of , with degrees of freedom (where each variable is divided by its degrees of freedom).
The F-ratio, in its various forms, can be used to compare whether the variances of two samples are equal (an assumption of several statistical tests), but it finds a much broader application in the context of analysis of variance (ANOVA) to analyze factorial experiments and in least-squares regression analysis (Rice, 1988).
• Identify the scale of measurement of a variable (nominal, ordinal, or interval/ratio) • Determine if a variable is discrete or continuous • Create and interpret frequency distribution tables, bar graphs, histograms, and line graphs
