Researchers at Texas A&M studied the effect of using standing height desks in an elementary school on the energy expended by nine students. In their paper about the study, they reported descriptive statistics for the nine students. These descriptive statistics were expressed as a mean plus or minus a standard deviation. One such descriptive statistic was the weight of students before using the standing desks, which was reported as 27.0±7.9 kilograms. (This exercise is also a warning to read carefully: that 27.0±7.9 is not a confidence interval, yet summaries in this form are common in scientific reports.) need to find standard error