This as-told-to essay is based on a conversation with Andrew Menaker, a psychologist and a day trading coach based in San Francisco. It has been edited for length and clarity. First of all, I had ...

Getting into the world of trading can seem daunting. Here are the key things to consider if you’re just starting out.

Corporate share repurchases are at a record high despite record high stock prices and an uncertain economy? What do they know? Should you follow suit?

You report changes in the stock market that are tenths of a percent. As a physical scientist, changes on this order are not typically significant; we call them noise. Is a change of a tenth of a ...