Uniform Distribution¶
Formula¶
\[
X\sim \mathrm{Uniform}(a,b),\qquad
f(x)=\frac{1}{b-a}\ \text{ for } a\le x\le b
\]
Plot¶
fn: 1
xmin: 0
xmax: 1
ymin: 0
ymax: 1.2
height: 280
title: Uniform PDF on [0, 1]
Parameters¶
- \(a<b\): interval endpoints
- \(x\): value in the interval
What it means¶
All values in the interval \([a,b]\) are equally likely in density terms.
What it's used for¶
- Baseline continuous distribution.
- Random initialization and simulation.
Key properties¶
- Mean \((a+b)/2\), variance \((b-a)^2/12\).
- Constant density on the interval.
Common gotchas¶
- Continuous uniform has \(P(X=x)=0\) for any exact point.
- "Equally likely values" for continuous variables refers to equal-length intervals.
Example¶
\(\mathrm{Uniform}(0,1)\) is commonly used for random sampling in simulations.
How to Compute (Pseudocode)¶
Input: distribution parameters and query values (for PMF/PDF/CDF or moments)
Output: distribution quantities
validate parameters
for each query value x (or count k):
evaluate the PMF/PDF/CDF formula from the card
optionally compute moments/statistics from known closed forms or by summation/integration
return the requested values
Complexity¶
- Time: Typically \(O(q)\) for \(q\) query values once parameters are known (assuming constant-time formula evaluation per query)
- Space: \(O(q)\) for output values (or \(O(1)\) for a single query)
- Assumptions: Parameter estimation/fitting cost is excluded; numerical special-function evaluation can affect constants for some families