How to Identify Best Battery Group
Company: Tesla
Role: Software Engineer
Category: Machine Learning
Difficulty: medium
Interview Round: Onsite
You have historical quality data for batteries that were randomly assigned to one of 5 groups. Each battery then goes through 3 different quality tests, and each test outcome is binary: pass or fail.
Describe a statistically sound way to determine which group has the best overall quality.
Your answer should address:
- how to define an overall quality metric from the 3 test results;
- how to compare the 5 groups even if the sample sizes are different;
- how to quantify uncertainty so you do not pick a winner based only on random variation;
- how to handle multiple-group comparison when deciding whether one group is truly better than the others.
Quick Answer: This question evaluates understanding of statistical inference, experimental design, and metric construction for binary test outcomes, including defining composite quality measures, handling unequal sample sizes, quantifying uncertainty, and addressing multiple-comparison issues.