For a given data set, standard deviation measures how spread out the numbers are from an average value. This measurement of ...

In response to my article, Is the Stock Market Too Concentrated?, which relied upon standard-deviation calculations to assess investment risk, a reader wrote: “My problem [with your argument] is ...

Understand what portfolio diversification is and why it's a crucial investment strategy. Learn how diversification can help ...

You may have heard people say that investing involves a tradeoff between risk vs. return. And that’s typically true. Investors usually need to take on greater risk to achieve higher returns. But what ...