notes上有句话：Generally, the evidence indecates that technical analysis does not produce abnormal profits, so we cannot reject the hypothesis that markets are weak-form efficient.没太明白这句话的意思。
既然在weak-form efficient market下面，无法通过technical analysis获取positive risk-adjusted returns，那么为什么不能够拒绝markets are weak-form efficient这个假设呢？不是应该证明了这个假设是对的吗？