Testing your knowledge is an essential part of learning, as it helps you evaluate your understanding of a topic and identify areas for improvement. This can be done through self-assessments, peer evaluation (mock interviews), and/or solving interview questions and problem sets.
When preparing for an interview, it’s important to understand that interview questions often test not only your knowledge but also your problem-solving skills, ability to think critically, and soft skills for effective communication. Practicing questions is one of the best ways to tackle these areas. Some topics you may see in a hedge fund data science interview include:
SQL
1. Write a basic query that counts the total transactions in the table.
Given anannual_paymentstable, answer the following questions and output each of them as a table.
- How many total transactions are in this table?
- How many different users made transactions?
- How many transactions listed as
"paid"have an amount greater or equal to 100? - Which product made the highest revenue? Use only transactions with a
"paid"status.
2. Calculate the percentage of total revenue made to date during thefirstandlastyears recorded in the table.
You’re generating a yearly report for your company’s revenue sources. Calculate the percentage of total revenue made to date during thefirstandlastyears recorded in the table. Round the percentages to two decimal places.
3. Find the average annual retention for a subscription product.
You’re given a table calledannual_paymentsfor an annually billed B2B SAAS subscription product. Users pay for three different products: 'PDF Editor','Cloud Storage', and'Mobile CRM'. How would you formulate a query to calculate the average annual retention (for each subsequent year) at the end of the year?
Algorithms
1. Write a function to find the total profit from investing in an index fund.
You’re given two lists:
- A dictionary of deposits and withdrawals into an index fund with timestamps.
- A daily price of the index fund by date.
Write a functionfund_returnto calculate the total profit gained from investing in the index from the start to the end date. You may only purchase and sell discrete shares of the index fund. For example, if you have23 dollarsand the price of the index is5 dollars, you can only purchase four shares.
Assume that the revenue (or loss) from the index fund is applied to the deposited funds at the beginning of every day based on the percentage increase in the price of the index and that the purchases (or withdrawals) are made before the end of each day.
2. Write a function to return the median value of a list.
You’re given a list of sorted integers in which more than 50% of the list is comprised of the same repeating integer. Write a function to return the median value of the list in O(1) computational time and space.
3. Write a function that filters out integers in an array if they’re less than another integer in a later index.
Given an integer arrayarr, write a functiondecreasing_valuesto return an array of integers so that the subsequent integers in the array get filtered out if they are less than an integer in a later index of the array.
Statistics and Probability
1. Find the probability of getting two cards of the same rank when drawing cards.
Let’s say that you’re drawing N cards (without replacement) from a standard 52-card poker deck. Each card is unique and part of 4 different suits and 13 different ranks.
Compute the probability that you will get a pair (two cards of the same rank) from a hand ofNcards.
2. Describe the difference between z and t-tests.
What are they used for? When should we use one over the other?
3. Compare softmax and logistic functions.
What is the difference between them? What makes them useful for logistic regression?
