交叉

交叉是最基本的信号并且受大多数交易员的欢迎，因为它能排除所有的情绪。最基本类型的交叉是一种资产价格的移动平均线从一端移动并在另一端结束。交易员用价格交叉来鉴别动量转移并作为一个基本的进入和退出策略。如下图所示，一个移动平均线之下的交叉表明下降趋势的开始，交易员通常把它当作开始或者关闭长期仓位的信号。相反，移动平均线之上的交叉则意味着新的上升趋势的开始。

 

第二种类型的交叉是短期移动平均线与长期移动平均线交叉。这是一个在一个方向强劲运动的信号。当短期移动平均线穿过长期移动平均线到其上面时发出一个买入信号。而短期移动平均线交叉到长期移动平均线下面时则产生卖出信号。如下图所示，这个信号非常客观，这也是它为什么这么流行的原因。

 

三交叉和移动平均线丝带

可以再增加移动平均线以增加图表的可靠性。许多交易员会在图表中设置5天、10天和20天移动平均线等待5天移动平均线向上穿过其他移动平均线而产生买入信号。等待10天移动平均线向上穿过20天移动平均线作为确认，这是减少错误信号的一种方式。增加移动平均线的数量是判断趋势强度和趋式持续可能性的最好方式。

 

这就引出了一个问题：如果你一直增加移动平均线将会出现什么情况呢？有些人认为如果一条移动平均线管用，那么10条或者更多条的效果会更好。 这使我们联想到一个成为移动平均线丝带的技术，正如下图所示，在一个图表中设置许多移动平均线以判断当前趋势的强度。当所有的移动平均线朝一个方向移动，那么趋势就很强烈。移动平均线在在相反防线顶部交叉则确定逆转。

 

适应不断变化环境需要采用不同的移动平均线周期。在计算中使用的时间周期越短，对价格变化的反映越明显。最常见的一种丝带是以50天移动平均线开始并到200天结束，每次递增10天。这种移动平均线能很好的鉴别长期趋势和反转。

 

过滤器

过滤器是在技术分析中增加特定交易信心的技术。例如，许多投资者要等到股票价格向上穿过移动平均线并且至少高于10%才会开始交易。这是为了保证交叉是有效的并减少错误的信号。太依赖过滤器的缺点是可能放弃一些机会并导致错失良机。当你不断调整过滤器的使用后会减少这些负面影响。当进行过滤的时候没有特定的规则，他只是一个使你投资更加有信息的额外工具。

 

移动平均包络线

使用移动平均的另一个策略被称为包络线。这一策略在移动平均线附近绘制出两个波段，用一个特定的百分率错列出来。例如在下图中，25天移动平均线附近放置了5%包络线。交易员通过观察这些波段确定他们是否是强烈的支撑和阻力区域。注意波段在到达一个包络线水平时通常会逆转。价格在超过这两个波段时通常会失去动力并向中间的移动平均移动。

 

Moving Averages: Strategies

 

By Casey Murphy, Senior Analyst ChartAdvisor.com 

 

Different investors use moving averages for different reasons. Some use them as their primary analytical tool, while others simply use them as a confidence builder to back up their investment decisions. In this section, we'll present a few different types of strategies - incorporating them into your trading style is up to you! 

 

Crossovers 

A crossover is the most basic type of signal and is favored among many traders because it removes all emotion. The most basic type of crossover is when the price of an asset moves from one side of a moving average and closes on the other. Price crossovers are used by traders to identify shifts in momentum and can be used as a basic entry or exit strategy. As you can see in Figure 1, a cross below a moving average can signal the beginning of a downtrend and would likely be used by traders as a signal to close out any existing long positions. Conversely, a close above a moving average from below may suggest the beginning of a new uptrend. 

 

The second type of crossover occurs when a short-term average crosses through a long-term average. This signal is used by traders to identify that momentum is shifting in one direction and that a strong move is likely approaching. A buy signal is generated when the short-term average crosses above the long-term average, while a sell signal is triggered by a short-term average crossing below a long-term average. As you can see from the chart below, this signal is very objective, which is why it's so popular. 

 

Triple Crossover and the Moving Average Ribbon 

Additional moving averages may be added to the chart to increase the validity of the signal. Many traders will place the five-, 10-, and 20-day moving averages onto a chart and wait until the five-day average crosses up through the others – this is generally the primary buy sign. Waiting for the10-day average to cross above the 20-day average is often used as confirmation, a tactic that often reduces the number of false signals. Increasing the number of moving averages, as seen in the triple crossover method, is one of the best ways to gauge the strength of a trend and the likelihood that the trend will continue. 

 

This begs the question: What would happen if you kept adding moving averages? Some people argue that if one moving average is useful, then 10 or more must be even better. This leads us to a technique known as the moving average ribbon. As you can see from the chart below, many moving averages are placed onto the same chart and are used to judge the strength of the current trend. When all the moving averages are moving in the same direction, the trend is said to be strong. Reversals are confirmed when the averages cross over and head in the opposite direction.

 

Responsiveness to changing conditions is accounted for by the number of time periods used in the moving averages. The shorter the time periods used in the calculations, the more sensitive the average is to slight price changes. One of the most common ribbons starts with a 50-day moving average and adds averages in 10-day increments up to the final average of 200. This type of average is good at identifying long-term trends/reversals. 

 

Filters 

A filter is any technique used in technical analysis to increase one's confidence about a certain trade. For example, many investors may choose to wait until a security crosses above a moving average and is at least 10% above the average before placing an order. This is an attempt to make sure the crossover is valid and to reduce the number of false signals. The downside about relying on filters too much is that some of the gain is given up and it could lead to feeling like you've "missed the boat". These negative feelings will decrease over time as you constantly adjust the criteria used for your filter. There are no set rules or things to look out for when filtering; it's simply an additional tool that will allow you to invest with confidence. 

 

Moving Average Envelope 

Another strategy that incorporates the use of moving averages is known as an envelope. This strategy involves plotting two bands around a moving average, staggered by a specific percentage rate. For example, in the chart below, a 5% envelope is placed around a 25-day moving average. Traders will watch these bands to see if they act as strong areas of support or resistance. Notice how the move often reverses direction after approaching one of the levels. A price move beyond the band can signal a period of exhaustion, and traders will watch for a reversal toward the center average. 

 

本文翻译由兄弟财经提供

文章来源：http://www.investopedia.com/university/movingaverage/movingaverages4.asp