Not shown in the statistics may have reversed the conclusions

Statistics are persuasive.So much so that people, organizations,and whole countries base some of their most important decisions on organized data.But there's a problem with that.Any set of statistics might have something lurking inside it,something that can turn the results completely upside down.For example, imagine you need to choose between two hospitals for an elderly relative's surgery.Out of each hospital's last 1000 patient's,900 survived at Hospital A,while only 800 survived at Hospital B.So it looks like Hospital A is the better choice.