The price and volume action is illustrated in blue bars for days when the stock closes higher and red for days when the stock falls. This is especially helpful in identifying significant buying or selling trends.
In both daily and weekly charts, the stock’s average volume over the past 50 days is plotted with a red line. This is helpful in comparing trading activity, especially when a stock reaches its optimal buy point. Each chart also shows the stock’s 50- and 200-day moving average, which often act as levels of support for stocks.
To learn more about chart reading, go to How To Read Stock Charts