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A Symbols

A.1 General notes

  • Greek letters represent population parameter values; roman letters represent sample values.

  • A Greek letter with a "hat" represents and estimate of the population value from the sample; i.e., μx represents the true population mean of X, while ˆμx represents its estimate from the sample.

A.2 Table of symbols

symbol pronunciation definition
μ meeYU generally, a population mean; sometimes, a model intercept. μx represents the mean of x
σ sigma lower case sigma is the standard deviation; σx is the standard deviation of X
σ2 sigma squared variance
ρ row population correlation; ρxy is the correlation in the population between X and Y
r row sample correlation; r_{xy} is the correlation in the sample between X and Y
Σ sigma the capital letter sigma in boldface represents a variance-covariance matrix
sigma upper case sigma is an instruction to add; e.g., Xi is the instruction to sum together all values of X.
β beta regression coefficient
is distributed as e.g., eN(μ,σ2) means that e is distributed as a Normal distribution with mean μ and variance σ2
γ gamma fixed effects, correlation coefficients in a mixed-effects regression
τ tau by-subject variance component (random effects parameter) in a mixed-effects regression
ω omega by-stimulus variance component (random effects parameter) in a mixed-effects regression
S0s S sub zero S by-subject random intercept effect for subject s
S1s S sub one S by-subject random slope effect for subject s