About stock charts
A stock chart shows data as points on a time continuum, such as days of the week. Stock values appear as a candlestick, a box with lines extending up and down from the ends. Open and close values mark the upper and lower edges of the box. High and low values mark the upper and lower points of the line.
Although a stock chart typically displays stock price data, you can also use a stock chart to show scientific data, such as temperature changes over time.
Candlestick stock chart
Candlestick stock charts contain boxes with lines extending up and down from the ends. The upper and lower edges are the open and close values of the stock. The upper and lower points of the line are the high and low values of the stock, as shown in Figure 7-15. The top and bottom of each box indicate the open and close values. If the close value is higher than the open value, the box is white. If the open value is higher than the close value, the box is shaded. This style immediately provides information about whether a stock posted a gain or a loss for a given day. The chart in Figure 7-15 shows that the stock posted a gain on the fourth and sixth day in the trading week and a loss on the other five days.
Figure 7-15 Candlestick stock chartBar stick stock chart
Bar stick stock charts consist of a vertical line with two horizontal lines called ticks attached to it. The upper and lower points of the vertical line are the stock open and close values. The ticks are the high and low values, as shown in Figure 7-16. The chart in Figure 7-16 shows the same data as the chart in Figure 7-15. As you can see, the candlestick stock chart shows the gain or loss pattern more clearly than the bar stick stock chart. The following example shows a stock with moderate fluctuation. When the stock is volatile on a given day, the two horizontal lines can appear far above or below the vertical line.
Figure 7-16 Bar stick stock chart