Roku (ROKU) has been on a downward spiral lately with significant selling pressure. After declining 11.3% over the past four weeks, the stock looks well positioned for a trend reversal as it is now in oversold territory and there is strong agreement among Wall Street analysts that the company will report better earnings than they predicted earlier.Guide to Identifying Oversold StocksWe use Relative Strength Index (RSI), one of the most commonly used technical indicators, for spotting whether a stock is oversold. This is a momentum oscillator that measures the speed and change of price movements.RSI oscillates between zero and 100. Usually, a stock is considered oversold when its RSI reading falls below 30.Technically, every stock oscillates between being overbought and oversold irrespective of the quality of their fundamentals. And the beauty of RSI is that it helps you quickly and easily check if a stock's price is reaching a point of reversal.So, by this measure, if a stock has gotten too far below its fair value just because of unwarranted selling pressure, investors may start looking for entry opportunities in the stock for benefitting from the inevitable rebound.However, like every investing tool, RSI has its limitations, and should not be used alone for making an investment decision.Why ROKU Could Bounce Back Before LongThe heavy selling of ROKU shares appears to be in the process of exhausting itself, as indicated by its RSI reading of 29.3. So, the trend for the stock could reverse soon for reaching the old equilibrium of supply and demand.This technical indicator is not the only factor that calls for a potential rebound for the stock. There is a fundamental indicator as well. A strong agreement among sell-side analysts covering ROKU in raising earnings estimates for the current year has led to an increase in the consensus EPS estimate by 5.5% over the last 30 days. And an upward trend in earnings estimate revisions usually translates into price appreciation in the near term.Moreover, ROKU currently has a Zacks Rank #1 (Strong Buy), which means it is in the top 5% of more than the 4,000 stocks that we rank based on trends in earnings estimate revisions and EPS surprises. This is a more conclusive indication of the stock's potential turnaround in the near term. You can see the complete list of today's Zacks Rank #1 (Strong Buy) stocks here >>>> Time to Invest in Legal Marijuana If you’re looking for big gains, there couldn’t be a better time to get in on a young industry primed to skyrocket from $17.7 billion back in 2019 to an expected $73.6 billion by 2027. After a clean sweep of 6 election referendums in 5 states, pot is now legal in 36 states plus D.C. Federal legalization is expected soon and that could be a still greater bonanza for investors. Even before the latest wave of legalization, Zacks Investment Research has recommended pot stocks that have shot up as high as +285.9%. You’re invited to check out Zacks’ Marijuana Moneymakers: An Investor’s Guide. It features a timely Watch List of pot stocks and ETFs with exceptional growth potential.Today, Download Marijuana Moneymakers FREE >>Want the latest recommendations from Zacks Investment Research? Today, you can download 7 Best Stocks for the Next 30 Days. Click to get this free report Roku, Inc. (ROKU): Free Stock Analysis Report To read this article on Zacks.com click here.