Generation of Random Variables

Methods of Generating Random Numbers

Since computers are deterministic machines, they cannot generate true randomness. There are two main approaches to generate random numbers:

1. Physical Random Number Generation

  • Uses physical devices (sensors) to capture natural phenomena
  • Converts the readings to digital form
  • Provides high-quality randomness
  • More expensive and complex to implement
  • Used in applications requiring high security or scientific accuracy

2. Pseudorandom Number Generation

  • Uses special algorithms called Pseudorandom Number Generators
  • Generates sequences that appear random
  • More efficient and cost-effective
  • Most commonly used method
  • Quality depends on the algorithm used

3. Hybrid Approach

  • Combines both methods
  • Uses operating system parameters as seed for randomness
  • Balances between quality and efficiency
  • Useful for applications requiring moderate randomness quality

Distribution Transformation

The random numbers generated by any of these methods will follow a specific distribution. To obtain numbers following a desired distribution, we need to:

  1. Generate random numbers using one of the above methods
  2. Transform these numbers to follow the target distribution
  3. Verify the transformed numbers match the desired distribution

Additional Resources

For a detailed understanding of random variables and their properties, please refer to the comprehensive writeup provided here.

Key Concepts to Understand

  • Probability distribution functions
  • Probability density functions
  • Transformation methods
  • Quality metrics for random number generation
  • Applications of different random number generation methods