Computers
Using Excel for Statistical Analysis - Terms You Should Understand Before You Start by Stephen Nelson
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Probability Distributions
The term probability refers to the likelihood that an event will happen. Probabilities range between 0 (impossible) and 1 (inevitable).
A probability distribution graphically depicts how probabilities are distributed over discrete values or ranges of the random variable. Probability distributions can take on several shapes. For example, a uniform probability distribution is rectangular-it occurs when there's an equal probability for every value of the random variable.
Another common probability distribution is the normal or bell curve. This occurs when there's a relatively high probability of a random variable taking a certain value or range and a symmetrically diminishing probability as you move away from this value.
Discrete versus Continuous Variables
A discrete variable is one that can't fall to an infinite number of digits. For example, the number of children in a family is a discrete number, in this case a non-negative integer. A continuous variable, on the other hand, can take on a value with any number of digits. For example, you can theoretically calculate the time it takes a person to run a mile down to the smallest fraction of a second.