Everyone must wear medical grade gloves in a sterile field. A sterile field is usually used during surgery. A sterile syringe and vial of medication. Surgical hand scrubs remove most bacteria from the skin before gloves are put on.
Standard score. In statistics, the standard score is the signed number of standard deviations by which the value of an observation or data point is above the mean value of what is being observed or measured. Observed values above the mean have positive standard scores, while values below the mean have negative standard scores. The standard score is a dimensionless quantity obtained by subtracting the population mean from an individual raw score and then dividing the difference by the population standard deviation.
There is also a direct relationship between standard scores and percentile ranks so that a standard score of 100 corresponds to a percentile rank of 50; a standard score of 90 is the same as a percentile rank of 25; and a standard score of 110 is the same as a percentile rank of 75.n this case, average performance typically falls between standard scores of 90 and 110. The farther away from that range, the more different a student s score is from the middle performance. Another statistically derived score is Percentile Ranks.