- Franco Arda

# How to add Standard Deviation to the Y-axis?

**Let’s say you have the stock price of [Tesla] on the Y-axis and time on the X-axis. You want to add an additional axis that shows the Standard Deviation (a.k.a. volatility in finance) for the last 30 days. How can you achieve that?
**

The following function calculates the Standard Deviation of [Tesla] for the last 30 days:

WINDOW_STEDV(SUM([Tesla], -30,0)). Now I add this Calculated Field (function) as a Dual Axis (Y-axis on the right). Ideally, I display the standard deviation is percentages.

The standard deviation is displayed on a Dual Axis.

Having the standard deviation on the Y-axis allows me to create an email alert (e.g. send an email alert if standard deviation >32%).

PS: Not long ago, that was an interview question for a Tableau project.

Franco