Statistical Methods for Psychology

Glossary of Symbols

Greek Letter Symbols

a Alpha: level of significance, probability of a Type I error

ai Treatment effect for the ith level of A

b Beta: probability of a Type II error

bi Standardized regression coefficient; treatment effect for the ith level of B

G Gamma function (related to factorial)

d Delta: noncentrality parameter; population effect size

Epsilon: symbols for correction factors for degrees of freedom in repeated-measures

analysis of variance

h^2 Eta squared: squared correlation ratio

Mu: population mean

Mean of the sampling distribution of means

r Rho: population correlation coefficient

Sigma (lower case): population standard deviation

Population variance

Error variance

Sigma (upper case): summation notation; variance-covariance matrix

t Kendall’s tau: a nonparametric measure of correlation

Treatment effect for the jth treatment

f Phi coefficient: a correlation coefficient computed for a 2 3 2 contingency table

Cramér’s phi: an extension of phi to contingency tables larger than 2 32

Chi-square statistic: most commonly used as test of contingency table

Friedman’s

c Psi: linear contrast

Omega-squared: most often an r-family measure of effect size

English Letter Symbols

a Intercept; number of levels of variable A

Regression coefficient—slope; number of levels of variable B

Intercept in multiple regression

d Effect size estimate

df Degrees of freedom

Unit of error associated with subject iin treatment j

E(MS) Expected mean square

eij

b 0

b, bi

v^2

x^2 F x^2

x^2

fC

tj

g

s^2 e

s^2 , s^2 X

s, sX

mX

m, mX

́N, ́~