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.
We'll begin with z scores. z scores can be computed by equating the mean of the raw score distribution to 0.00 and the standard deviation to 1.00. T-scores are directly related to z scores. With T-scores, the mean of the raw score distribution is equated to 50, and the standard deviation is equated to 10. Therefore, a z score of +1.00 would be equal to a T-score of 60. In general z scores are expressed as decimals carried out to the hundredths place and T-scores are expressed as whole numbers. Thus, a z score of -3.00 is equal to a T-score of 20.