The uniform distribution is one of the simplest and most intuitive probability distributions. If every outcome in a range is equally likely, you're dealing with a uniform distribution.
Using NumPy, Python makes it easy to generate, analyze, and visualize uniformly distributed data — a key skill for simulations, data analysis, and testing.
What is a Uniform Distribution?
A uniform distribution describes a situation where every value within a specified range is equally likely to occur.
There are two main types:
-
Discrete Uniform Distribution – finite, equally likely outcomes (e.g., rolling a die).
-
Continuous Uniform Distribution – all values in a real interval have equal probability (e.g., random float between 0 and 1).
This article focuses on the continuous uniform distribution as implemented in NumPy.
Uniform Distribution Formula
For a continuous uniform distribution between a
and b
, the probability density function (PDF) is:
f(x)=1b−afor a≤x≤bf(x) = \frac{1}{b - a} \quad \text{for } a \leq x \leq b
Real-Life Examples
Use Case | Description |
---|---|
Simulation | Random delays or noise in systems |
Games | Generating random positions or scores |
Testing | Generating synthetic test data |
Monte Carlo | Sampling over a flat probability space |
NumPy’s Uniform Function
NumPy provides the uniform()
method via its random number generator:
Syntax
numpy.random.Generator.uniform(low=0.0, high=1.0, size=None)
Parameters
Parameter | Description |
---|---|
low |
Lower bound of the interval |
high |
Upper bound of the interval |
size |
Number of samples or shape of output array |
✅ Returns
A float or NumPy array of uniformly distributed values.
✅ Example: Generate Uniform Random Numbers
import numpy as np
rng = np.random.default_rng(seed=42)
data = rng.uniform(low=0, high=10, size=1000)
This generates 1000 values uniformly distributed between 0 and 10.
Visualizing Uniform Distribution
import matplotlib.pyplot as plt
import seaborn as sns
sns.histplot(data, bins=20, kde=False, color='skyblue')
plt.title("Uniform Distribution (0 to 10)")
plt.xlabel("Value")
plt.ylabel("Frequency")
plt.grid(True)
plt.show()
You should see a fairly flat histogram — every value has roughly the same frequency.
Mean and Variance
For a continuous uniform distribution:
-
Mean: (a+b)/2(a + b) / 2
-
Variance: (b−a)2/12(b - a)^2 / 12
low, high = 0, 10
mean_theoretical = (low + high) / 2
var_theoretical = ((high - low) ** 2) / 12
mean_sample = np.mean(data)
var_sample = np.var(data)
print("Theoretical Mean:", mean_theoretical)
print("Sample Mean:", round(mean_sample, 2))
print("Theoretical Variance:", var_theoretical)
print("Sample Variance:", round(var_sample, 2))
Try Different Ranges
Uniform between -5 and 5
data = rng.uniform(low=-5, high=5, size=1000)
sns.histplot(data, bins=20, kde=False, color='lightgreen')
plt.title("Uniform Distribution (-5 to 5)")
plt.xlabel("Value")
plt.show()
Full Example: Simulating Random Delays
Let’s simulate 1000 random network delays that occur uniformly between 20ms and 120ms.
import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns
rng = np.random.default_rng(seed=123)
# Simulate delays
delays = rng.uniform(low=20, high=120, size=1000)
# Plot
sns.histplot(delays, bins=30, kde=False, color='orange')
plt.title("Simulated Network Delays (20ms to 120ms)")
plt.xlabel("Delay (ms)")
plt.ylabel("Frequency")
plt.grid(True)
plt.show()
# Stats
print("Average Delay:", round(np.mean(delays), 2), "ms")
print("Minimum Delay:", round(np.min(delays), 2), "ms")
print("Maximum Delay:", round(np.max(delays), 2), "ms")
Tips
Tip | Why It Matters |
---|---|
✅ Set a random seed during development | Ensures reproducibility |
✅ Use 2D/3D shapes via size=(n, m) |
Useful in simulations and matrix data |
✅ Use np.clip() if post-processing changes values |
Keeps data in range |
✅ Combine with other distributions | For hybrid or multi-phase simulations |
⚠️ Common Pitfalls
Pitfall | Explanation |
---|---|
❌ low >= high |
Will raise a ValueError |
❌ Forgetting the size parameter |
Only returns a single float |
❌ Assuming a bell curve | Uniform distribution is flat, not normal |
❌ Modifying values outside [low, high] | Loses uniformity; use clip to stay in range |
Uniform vs Other Distributions
Distribution | Shape | Use Case |
---|---|---|
Uniform | Flat | Equal probability sampling |
Normal | Bell curve | Natural processes |
Poisson | Skewed | Count events in time/space |
Binomial | Discrete | Success/failure over trials |
Conclusion
The uniform distribution is a foundational concept in statistics and simulation. With NumPy, it becomes effortless to:
-
Generate random numbers across ranges
-
Simulate real-world processes like delays or randomness
-
Visualize and validate uniformity
-
Perform statistical analysis
Key Takeaways
-
Use
uniform(low, high, size)
for continuous uniform data. -
Use
np.random.default_rng()
for better random number generation. -
Validate your samples with mean/variance comparisons.
-
Use histograms to visually confirm uniformity.