A past coaching client of mine interviewed for an entry-level Data Science job in Los Angeles that paid $110k per year.

Here's the 19 interview questions they were asked:

(how many of these could you answer?)

𝐒𝐭𝐚𝐭𝐢𝐬𝐭𝐢𝐜𝐬 🔢

1. Explain the difference between population variance vs sample variance

2. Describe a p-value to a 13-year-old (8th grader)

3. What Does an R-Squared Value of 0.9 Mean?

𝐒𝐭𝐚𝐭𝐢𝐬𝐭𝐢𝐜𝐬 (Continued) 🔢

4. What are some metrics to evaluate how predictive your logistic regression model is?

5. Can you explain precision vs. recall? How does that relate to an ROC curve?

𝐒𝐐𝐋 ⚙️

6. What is a database view?

7. What's the difference between a primary key & a foreign key?

8. Have you had to troubleshoot a slow query before? How did you do it?

9. When should you use a Sub-Query vs. CTE?

𝐒𝐐𝐋 (Continued) ⚙️

10. Can you write a SQL query to find the 3-day rolling average?

(very similar to this Twitter SQL interview question on