What are the odds of an up day?

I had an idea. We have had 4 days of selling, and the market moves in UP and DOWN waves, not a straight line. This idea is not based on fundamental analysis, news; more it is based on the Elliot Wave principle. I'm not suggesting you go long yet, just keep an eye out for an up day. If not today, maybe monday. My multipl year studies show Fridays tend to be down days and monday tends to be up days. This 100% contradicts what it says on investopedia. I think their idea is a scam.