Adam Hayes, Ph.D., CFA, is a financial writer with 15+ years Wall Street experience as a derivatives trader. Besides his extensive derivative trading expertise, Adam is an expert in economics and ...

Although there are many functions in the base package of R, sometimes there may not be a function that does exactly what you want. In this case, R allows users to create their own functions and call ...

Investopedia contributors come from a range of backgrounds, and over 25 years there have been thousands of expert writers and editors who have contributed. Thomas J. Brock is a CFA and CPA with more ...

We independently review everything we recommend. When you buy through our links, we may earn a commission. Learn more› By Meirav Devash Bad mascara can ruin your day, clumping your eyelashes into a ...