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Module 4 · Probability Module contents
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Uniform Distribution

The uniform distribution describes an uncertain situation where every possible outcome across a defined range is equally likely.

In a discrete uniform distribution, a finite number of distinct outcomes share the exact same probability.

For example, rolling a fair six-sided die follows a discrete uniform distribution where each number from one to six has a one-sixth chance.

In a continuous uniform distribution, the probability density is constant across an interval, creating a flat rectangular shape.

Uniform distributions serve as standard baseline models when an analyst possesses no reason to believe any outcome is more probable than another.

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Uniform Distribution, in more detail

The uniform distribution represents the state of maximum ignorance where all outcomes across a defined interval share equal likelihood.

It serves as the baseline reference model in probability theory and simulation modelling.

In the discrete uniform distribution across n items, each individual item possesses an identical probability of one divided by n.

Rolling a fair die or selecting a random card from a shuffled deck are classic physical examples of discrete uniform models.

In the continuous uniform distribution between limits a and b, the probability density function is constant at one divided by b minus a.

The probability of landing in any sub-interval depends solely on the length of that sub-interval, not its position on the axis.

The expected value of a continuous uniform distribution sits at the exact midpoint: a plus b divided by two.

Its variance equals the squared range, b minus a squared, divided by twelve.

Pseudo-random number generators in software typically generate continuous uniform values between zero and one as their native output.

Other continuous probability distributions, like the normal or exponential, are created by applying mathematical transforms to uniform draws.

In Bayesian statistics, uniform distributions are frequently used as uninformative prior distributions when no prior knowledge exists.

However, assuming a uniform prior across unbounded parameters creates improper mathematical distributions that cannot integrate to one.

Furthermore, a uniform distribution on a parameter does not remain uniform under non-linear transformations of that parameter.

In business analysis, assuming customer demand is uniform can lead to poor inventory decisions if sales actually cluster centrally.

A common mistake is assuming that any flat histogram implies an underlying uniform distribution without testing for sample noise.

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Question 1
A computer random number generator produces values continuously between 0 and 10 with equal likelihood everywhere. What distribution is this?
Probability

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