The below chart represents 19 consecutive days of QC values…

The below chart represents 19 consecutive days of QC values for a particular serum analyte. If on the 20th day (the 20th value), the result is above +1SD, which of the following is true? The mean is the solid black line in the middle, the wide dotted blue lines are +/-1SD , the dotted green lines are +/-2SD, and the top and bottom dotted blue lines are +/-3SD.  Question 30.png