, Statistical Symbols
Symbols are listed in order of their appearance in the text.
X A single element normally distributed population lies
from the population mean; or the
N Number of elements in a population
number of standard errors by which
n Number of elements in a sample a random sample mean lies from the
population mean
p The probability of an event occur-
ring. In reports of statistical signifi- µx– The mean of the random sampling
cance, p is the probability that the distribution of means
result could have been obtained by σx– Standard error or standard error of
chance—i.e., the probability that a the mean (standard deviation of the
type I error is being made random sampling distribution of
q The probability of an event not means) [SEM or SE]
occurring; equal to (1 – p) Sx– Estimated standard error (estimat-
ƒ Frequency ed standard error of the mean)
C Centile (or percentile) rank; or t The number of estimated standard
confidence level errors by which a random sample
mean lies from the population mean
Mo Mode
df Degrees of freedom
Mdn Median
α The criterion level at which the
µ Population mean null hypothesis will be accepted or
– rejected; the probability of making
X Sample mean
a type I error
∑ The sum of
b Probability of making a type II error
x Deviation score
c2 Chi-square; a test of proportions
σ2 Population variance
r Correlation coefficient
S2 Sample variance
r Rho; Spearman rank order correla-
σ Population standard deviation (SD) tion coefficient
S Sample standard deviation (SD) r2 Coefficient of determination
z The number of standard deviations b Regression coefficient; the slope of
by which a single element in a the regression line
, High-Yield TM
Biostatistics, Epidemiology, &
Public Health
FOURTH EDITION