Monday is the best day for you to buy your bitcoin?

In the graph, we could easily see and conclude that Mondays are the top average return of all days in a week. Also, we could see that Wednesday and Thursday that has average return of -0.09% and -0.23%.
In my opinion, I think for long term investment these days doesn't really matter anymore as long as we do buy low and sell high in the market, but I do believe that this analysis is on point in weekly investment or short term investment.
What are your thoughts about this?
bitcoin price can not prediction it mean we can not focus on price weekly because the next week not sure same. so we have to see market condition than based from price weekly . for me i do not buy bitcoin for now because waiting for the trend, when bitcoin go? up trend or down trend to minimize the risk for me in trading