Question

a shipment of marbles with a mean diameter of 27mm and a standard deviation of 0.15mm is normally distributed by how many standard deviations does a marble with a diameter of 26.85mm differ from the mean

Answer 1

z = (x - mu)/sigma
z = (26.85 - 27)/(0.15)
z = (-0.15)/(0.15)
z = -1
The result of -1 indicates that the raw score (26.85) is exactly 1 standard deviation below the mean.

Answer 2

The answer to the question is 1....... Hope it helps, Have a nice day :)