Probability distribution
A function that describes the probabilities of possible outcomes in a "sample space," which is a set that includes all possible outcomes.
Random variable
A variable that is itself a function of the result of a statistical experiment in which each outcome has a definite probability of occurrence.
Determinism
The theory that phenomena are causally determined by preceding events or natural laws; hence in this context, a "deterministically derived number" can be a system cost value derived from the cost of an earlier system.
Standard deviation (sigma value)
An index that characterizes the dispersion among the values in a population; it is the most commonly used measure of the spread of a series of values from their mean.
Bias
The expected deviation of the expected value of a statistical estimate from the quantity it estimates.
Correlation
A measure of the joint impact of two variables upon each other that reflects the simultaneous variation of quantities.
Percentile
A value on a scale of 100 indicating the percent of a distribution that is equal to or below it.
Monte Carlo sampling
A modeling technique that employs random sampling to simulate a population being studied.
Root-mean-square
The square root of the arithmetic mean of the squares of a set of numbers; a single number that summarizes the overall error of an estimate.