# A Practical Guide to Quantitative Finance Interviews

If you’re preparing for quantified life sciences interviews, you’ll need a practical guide to quantitative finance interviews. This book can help you zero in on the various key terms and concepts that are often tested during these interviews. In this new book we examine over 200 actual quant interview questions and offer valuable insights into just how to ace quant interviews. Armed with this knowledge, you’ll be well prepared to shine at your quant job interview.

Quotient theory is used to describe the various financial metrics used in the field of banking, insurance, and other financial services. A key concept of quotient theory is the idea that there are two types of individuals: divisible agents and divisible substances. According to quotient theory, individuals are divisible agents when their actions create a future result that is easily measurable, while substances are divisible substances when their actions create an impossible future result. A perfect example of a divisible agent is a stock price, which can’t be changed (a substance) or destroyed (a stock). Accordingly, it follows that any time an individual acts upon a divisible object, the effect on that object is easily measured and therefore the price of the stock will be divided into its parts.

This book covers many important topics that will be used in quant interview preparation. The first chapter focuses on the use of stock prices as a measure of value. Chapter two discusses traditional accounting practices and their application to the financial world. Specifically, the book covers the debate between qualitative and quantitative measures, the difference between correlation and causation, and the use of momentum in measuring financial risk. The third chapter focuses on the theoretical framework of quantitative finance.

Quotient theory is the subject of the last two chapters of this book. In the first chapter, the author examines the different methods of measurement, and then uses his or her experiences and observations as a practitioner to compare and contrast these methods. In the second chapter, the author applies quantitative techniques to real case studies and discusses the pitfalls of relying on empirical evidence in the context of quantitative finance. Finally, the last chapter presents a brief review of important issues regarding interpreting the quantitative data.

The focus of the next chapter is on interpreting estimates in terms of deviation. It starts with a simple example, presenting two possible outcomes for a mathematical equation: the first one being a prison prisoner given n and a prison nurse/prison guard ratio of m. The second outcome is the Prison Guard/Prison inmate ratio is multiplied by a Prisoner’s v equal to m. The author applies a prisoner’s deviation to the log-likelihood function and interprets this as a measure of the likelihood that the prisoner will escape in a given amount of time.

An implemented annotation type, called the “igraphal code” is used to provide quantitative reasoning support for a model in which the output of an algorithm is a set of real numbers rather than graphical expressions. This chapter describes two types of coding, namely the open or finite coding, and the closed or infinite coding. The finite coding involves a finite list of inputs that are used in computing the output; the infinite coding has no bound on the number of outputs. The focus of this chapter is to show how to use the appropriate implemented annotations. In previous editions, we have encountered several ambiguous parameter settings, and the author provides a detailed description of these and how to properly handle them throughout a spreadsheet.

The final chapter considers topics relevant to the practice of quantitative interviewing. One way to obtain information about the personality of a prospective applicant is by using cognitive brain teasers to estimate her psychological character. The author presents and discusses a sample. Specifically, she uses a battery of psychological tests and creates a puzzle to answer each test. Finally, she concludes that the personality factors most predictive of quantitative behavior are intelligence, personality, and willingness to take risks.

Quantitative analysis is the study of data and its trends. The author presents a number of useful exercises to supplement the task and to assist with the reasoning part of the Quantitative Analyst’s job. Specifically, she describes prisoner problems, the R-squared value problem, and hat colors and shade preference. She discusses the meaning of “a nice color,” the use of quadratic, binomial, and multiple regression models, and the validity of ordered correlated variables. Finally, she presents Prison Income Hypothesis and discuss the importance of Prison Income Theory (PCFT) for quantitatively analyzing prisoner earnings and cost.