summation - sum of all values in range ∑ summation of series ∑∑ double summation double summation that occurs most frequently in Mo mode population MR 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 median / second 50% of population are below this value Q2 quartile = median of samples Q3 upper / third quartile 75% of population are below this value x = (2+5+9) / 3 = x sample mean average / arithmetic mean 5.333 s 2 = 4 sample variance population samples variance estimator 2 sample standard population samples standard deviation s s = 2 deviation estimator zx zx = (x-x) / sx standard score X ~ ~ of X distribution of random variable X X N(0,3) N(μ,σ2) gaussian distribution X ~ N(0,3) ~ U(a,b) uniform distribution equal probability in range a,b X U(0,3) exponential exp(λ) f (x) = , x≥0 λe-λx distribution
∑ summation summation - sum of all values in range of series ∑∑ double summation double summation Mo mode that occurs most frequently in population MR 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 x sample mean average / arithmetic mean x = (2+5+9) / 3 = 5.333 2 sample variance population samples variance estimator s 2 = 4 s sample standard deviation population samples standard deviation estimator s = 2 zx standard score zx = (x-x) / sx X ~ of X distribution of random variable X X ~ N(0,3) N(μ,σ2) gaussian distribution X ~ N(0,3) U(a,b) uniform distribution equal probability in range a,b X ~ U(0,3) exp(λ) exponential distribution f (x) = λe-λx , x≥0
basic_math_symbols.docx