Peabody Energy Corp (NYSE:BTU) stock has been chopping lower since its Nov. 6 52-week high of $29.94, down 10% in just the last week. The shares could be headed for a short-term bounce, however, as the pullback has them running into a short-term "buy" signal. BTU just moved below the bottom band of its 20-day Bollinger Bands. Per Schaeffer's Senior Quantitative Analyst Rocky White, the shares moved higher after the past nine tests of this trendline, averaging a one-month gain of 6.4%. From its current perc ...