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Glossary of Symbols and Abbreviations

y^x	y to the power of x (also seen as y**x or y^x)

^Key	Ctrl + another Key

/	divided by (see calculator for operator precedence)

*	multiplied by (see calculator for operator precedence)

abs(x), \|x\|	absolute value of x without regard to sign

alpha, α	significance level of a hypothesis test (also type I error rate). 1-a is the level of the confidence interval

ANOVA	analysis of variance

beta, β	type II error rate (1-power)

CI	confidence interval, see confidence intervals

df	degrees of freedom

e	base of natural logarithms (2.718281...)

k!	factorial , in simplest terms factorial of k is the product of all integers from 1 to k, with 0! defined as 1, a fuller definition relates factorial to the gamma function as gamma (k+1) which enables the calculation of fractional factorials

ln(x)	natural (base e) logarithm of x, the natural logarithm of x is the value of y such that x is equal to the e constant raised to the power of y, remember that ln(1) = 0, ln(0) = minus infinity and ln(a/b)=ln(a)-ln(b), see also transformations

MS	mean square

μ	mean of a population - see also

n	sample size (population sized is usually referred to as N)

P	probability of the data (or more extreme data) arising by chance, see P values

p	proportion of a sample with a given characteristic

	q hat, the hat symbol above the q means "estimate of"

r	Pearson's product moment correlation coefficient

SD	standard deviation (of a sample, ) - a measure of variability around the mean - Greek lower case sigma (σ) is used for population standard deviation.

SE	standard error (of sample mean, ) - a measure of uncertainty of the estimate of a statistic (e.g. sample mean) and used to derive confidence intervals for the population value of the statistic

sqr(x)	square root of x, or

	sum of all (1 to n) x values

	product of all (1 to n) x values (x₁ * x₂ * x₃ etc.)

VAR	variance (of the mean, ), greek σ² for populations and s² for samples

vs.	versus

x	individual value from a population or sample

	x bar (bar symbol above the x denotes mean) is a sample mean (arithmetic mean, ), see also μ

z, Φ	standardized normal deviate (from standard normal distribution)