Here at Zacks, we focus on our proven ranking system, which places an emphasis on earnings estimates and estimate revisions, to find winning stocks. But we also understand that investors develop their ...

Standard deviation describes how much variability—or fluctuation—exists within a data set. The standard error of the mean (SEM) indicates how accurately a data set represents the true population by ...

Select Medical (SEM) came out with quarterly earnings of $0.18 per share, missing the Zacks Consensus Estimate of $0.19 per share. This compares to earnings of $0.36 per share a year ago. These ...