Separating Two Bell Distributions | Dataford Interview Questions

Given two bell-shaped populations with unknown parameters and labels, how would you separate them?

Assume the labeled observations are stored in a single table and you need to assign each unlabeled row to one of the two populations. Write a SQL query that returns the predicted population for every unlabeled observation, using the labeled rows to derive the separation rule.

Output

One row per unlabeled observation
Columns: observation_id, predicted_population
Include only rows where label IS NULL
Sort by observation_id ascending

Schema

observations

Column	Type	Description
observation_idPK	INT	Unique observation identifier
measurement	NUMERIC(10,4)	Observed numeric value
label	VARCHAR(20)	Known population label, null for unlabeled rows

Your question is Separating Two Bell Distributions. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Given two bell-shaped populations with unknown parameters and labels, how would you separate them?

Output

One row per unlabeled observation
Columns: observation_id, predicted_population
Include only rows where label IS NULL
Sort by observation_id ascending

Schema

observations

Column	Type	Description
observation_idPK	INT	Unique observation identifier
measurement	NUMERIC(10,4)	Observed numeric value
label	VARCHAR(20)	Known population label, null for unlabeled rows

Your question is Separating Two Bell Distributions. Start with the requirements and the one table in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.