Symbols Flashcards
What do X, s denote?
Statistics
What do μ, σ denote?
Parameters
μ
mew
mean of a population
σ
lowercase sigma
standard deviation of population or probability distribution
What does X or Y represent?
variable you have measured (eg IQ)
in linear regression:
X: predictor variable (s)
Y: variable you’re trying to predict
Xi (X sub i)
i-th score (i is subscript)
can be a number between 1 and N
eg., score of participant number 10 = X sub 10
N
total number of people or scores (sample size)
∑X
Summation
X1 + X2 + X3 + … XN = “the sum of the variable X from i=1 to N”
∑
uppercase sigma
indicates the operation of summation
N
∑ Xi
i=1
numbers below and above the sigma indicate the range (first and last scores) to be summed (1 to N)
x̅
x bar
mean of a sample
η
eta
a correlation coefficient used used to describe the
strength of a curvilinear relationship
r
Pearson r
a correlation coefficient used to describe the strength of a linear relationship
rs (s is subscript)
rho
the Spearman rank order correlation
coefficient; can be used to describe the strength of a linear relationship if one or both variables are measured on an ordinal scale
rb (b is subscript)
the biserial correlation coefficient; can be used to describe the strength of a linear relationship if one of the variables is interval or ratio and the
other is dichotomous
