The z-score is only defined if one knows the population parameters; if one only has a sample set, then the analogous computation with sample mean and sample standard deviation yields the Student's t-statistic.hus, a positive standard score indicates a datum above the mean, while a negative standard score indicates a datum below the mean.
Nemanja Matic dictates how Chelsea play... of all the players Jose Mourinho wanted to avoid losing, he was perhaps top of the list. Of all the players Jose Mourinho wanted to avoid losing at this critical point in the season, Nemanja Matic was perhaps top of his list. Eden Hazard, Cesc Fabregas, Diego Costa or John Terry would all be missed, of course, but Matic dictates how Chelsea plays. His prowling presence, tackling strength and defensive acumen in midfield offers more freedom to the creative players, especially Fabregas in his deeper role.
At the international level, RakitiÄ plays for the Croatian national team. Although naturally a product of Switzerland's youth level, RakitiÄ pledged his international career to his parents' country of Croatia instead.