Trades in the feed

What this Poisson process interview question tests

This is an easy probability question combining Poisson arrival processes with independent event classification. It appears in statistics and data-analysis rounds at trading firms, where candidates must model real market feeds and reason about message arrival patterns.

To solve questions like this, you identify the base arrival rate, condition on a specific time window, then apply the appropriate probability distribution. The question rewards clean setup: converting the arrival rate to the relevant time scale, recognizing which events you care about, and applying standard formulas without arithmetic errors.

• Poisson process scaling and time windows
• Filtering a Poisson stream by independent event probability
• Computing exact probabilities for discrete outcomes