Probability & Statistics
3 problems · 2 with full explanations
0 Easy2 Medium0 Hard
Probability problems may require expected value computation, random sampling, or reservoir sampling. Key concepts: linearity of expectation, conditional probability, and geometric distribution. Reservoir sampling picks k items from a stream of unknown length in O(n) time and O(k) space.
How to practice
To practice Probability & Statistics problems effectively, start with the Easy problems listed below, trace through each solution on paper, then re-implement without looking. When you can recognise the probability & statistics pattern within 30 seconds of reading a new problem, move on to Medium difficulty. Use the related topic pages and our study guide for a structured progression.