Estimate Customer Reviews Posted on Amazon.com on a Typical Monday

Estimate the total number of customer reviews posted across Amazon.com on any given Monday. Walk the interviewer through how you scope the question, the equation you build, the assumption behind each input, the arithmetic, and how you check that the result is reasonable. ```hint Follow the item, not the calendar Most reviews come from people who bought something and received it. Think about what drives the number of reviews, and how long after a purchase a review usually arrives, before you decide what makes a Monday different from other days. ``` ### Clarifying Questions - Does Amazon.com mean only the US storefront, or every Amazon marketplace worldwide? - What counts as a review: only written product reviews, or star ratings without text too? Are digital items such as e-books and apps in scope? - Is this a typical Monday, or one tied to a peak such as Cyber Monday or the weeks after the winter holidays? - Should a review count when it is submitted, or only once it is published after moderation? ### What a Strong Answer Covers - Scope fixed up front: which storefront, which review types count, and what kind of Monday. - A clear equation linking purchases to reviews, with every input labeled as an assumption and given a round number. - Correct arithmetic carried through to a headline number and a plausible range. - A reasoned Monday adjustment that keeps the week's total consistent, and an account of the lag between purchase and review. - A sanity check from an independent angle, and the assumption the answer is most sensitive to. ### Follow-up Questions - How would the count change on Cyber Monday, and why might the effect show up on later days instead? - Which input would you most want real data for, and how would you get it? - Amazon wants more reviews on products that have very few. Which lever in your equation would you try to move, and how?