It could be time to buy the VanEck Vectors Oil Services ETF OIH. It’s oversold and it's also at support. Both of these dynamics may result in a rally.

Most of the trading that occurs in the stock market is done by algorithms that are based on probability theory. The theory says that 95% of all trading should be within two standard deviations of the average price.

On the chart below, the red line is two standard deviations below this important threshold. OIH is currently trading below it. This will draw buyers into the market and they could push the price up.

In April when OIH fell to the $175 level, it was oversold like it is now. A large move higher followed. It could happen again.

(Click on image to enlarge)