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Statistical Symbols


Statistical Symbols

variance
Symbol Symbol Name Meaning
summation summation – sum of all values in range of series
∑∑ double summation double summation
μ population mean mean of population values
E(X) expectation value expected value of random variable X
E(X | Y) conditional expectation expected value of random variable X given Y
var(X) variance variance of random variable X
σ2 variance of population values
s 2 sample variance population samples variance estimator
s sample standard deviation population samples standard deviation estimator
std(X) standard deviation standard deviation of random variable X
σX standard deviation standard deviation value of random variable X
Mo mode value that occurs most frequently in population
MR mid-range MR = (xmax + xmin) / 2
Md sample median half the population is below this value
Q1 lower / first quartile 25% of population are below this value
Q2 median / second quartile 50% of population are below this value = median of samples
Q3 upper / third quartile 75% of population are below this value
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X
sample mean average / arithmetic mean
zx standard score
X ~ distribution of X distribution of random variable X
N(μ,σ2) normal distribution gaussian distribution
gamma(c, λ) gamma distribution
exp(λ) exponential distribution
U(a,b) uniform distribution equal probability in range a,b
Poisson(λ) Poisson distribution
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