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Scale AI·Machine Learning Engineer·Technical Phone Screen·Intermediate

Intermediate
May 2026

Summary

Scale AI ML engineer interview with a probability/statistics question that felt deceptively simple at first glance.

Questions Asked (1)

Q1

If you have ten points uniformly distributed across the interval [0, 1], what is the distribution of the gap between the 5th and 6th order statistics?

Algorithms & Data StructuresTechnical Trade-offs
Author's notes

Took me a second to even parse what they were asking.

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AI HintsAI Generated

Suggested Approach

Recognize that the gap between the 5th and 6th order statistics is the spacing between the two middle order statistics. Use the known result that for n uniform points, the joint distribution of spacings is Dirichlet, and the marginal distribution of any single spacing is Beta(1, n). Then apply the specific parameters n=10 and the fact that the gap is a single spacing.

Pro tip: Connect the result to practical ML applications, such as understanding the distribution of distances between nearest neighbors in embedding spaces or the expected gap in quantile-based data splits, to show depth beyond the math.

1. Define the problem

Clarify that the 5th and 6th order statistics are the two middle values when the 10 points are sorted. The gap is the difference between them.

2. Recall the distribution of spacings

For n points uniformly distributed on [0,1], the spacings (including the endpoints) follow a Dirichlet(1,...,1) distribution. Each individual spacing (excluding endpoints) is Beta(1, n).

3. Identify the specific spacing

The gap between the 5th and 6th order statistics is the 5th spacing (if we consider spacings between consecutive order statistics). Since there are 10 points, there are 9 internal spacings, each Beta(1,10).

4. State the distribution

Thus, the gap follows a Beta(1,10) distribution. Its density is f(x)=10(1-x)^9 for 0<x<1. The expected gap is 1/11, and the variance is 9/((11)^2*12) = 9/1452 ≈ 0.0062.

5. Discuss implications

Mention that the distribution is skewed, with most gaps small but occasional large gaps. This is relevant for understanding data sparsity in high-dimensional spaces or in quantile-based methods.

Key Points to Mention

  • Order statistics and their properties
  • Uniform distribution on [0,1]
  • Spacings between order statistics
  • Dirichlet distribution for spacings
  • Beta distribution parameters (1, n) for a single spacing
  • Expected value and variance of the gap

AI-generated suggestions, not part of the candidate's original notes. May be inaccurate — verify before relying on them.