# Ace your next data science interview

Get better at data science interviews by solving a few questions per week. Join thousands of other data scientists and analysts practicing for interviews!

## How it works?

### We write questions

Get data science interview questions frequently asked at top companies.

### You solve them

Solve the problem before receiving the solution the next morning.

## The Schedule

We send data science interview questions 3x per week

### Monday

### Tuesday

### Wednesday

### Thursday

### Friday

### Saturday

## Sample Questions

### Question

Suppose there are 15 different color crayons in a box. Each time one obtains a crayon, it is equally likely to be any of the 15 types. Compute the expected # of different colors that are obtained in a set of 5 crayons. (Hint: use indicator variables and linearity of expectation)

### Solution

We enumerate the crayons from 1 to 15. Let Xi indicate when the i^{th}crayon is among the 5 crayons selected. So, E(Xi) = Pr {Probability that at least one type i crayon is in set of 5} E(Xi) = 1 – Pr {no type i crayons in set of 5} E(Xi) = 1 – (14^{5}/15) Therefore, the expected # of crayons is: = ∑^{15}E(Xi) = 15[1-(14^{5}/15))] = 4.38

## See what others are saying

The majority of premium users *(90%++)* who canceled their subscription did so because they **landed a job!**

Data Interview Qs helped me cover all the basics of technical data science interviews, from SQL/Python to probability/statistics. The confidence/knowledge I gained from the service was incredibly useful, helping me land a data scientist position at Red Hat.

I've been on the mailing list since the initial beta, and found the questions to be very helpful with the technical side of my data science interview at Facebook, ultimately helping me land a role.

Data Interview Qs has been a great way to stay relevant with my data skills at Facebook, and has given me an edge in my Master’s Program in Data Science at Georgia Tech! It’s awesome to get a wide variety of questions and solutions sent to me on a regular basis.