A Meteorological Office Keeps Records of the Annual Precipitation in Different

Multiple Choice

A meteorological office keeps records of the annual precipitation in different cities. For one city, the mean annual precipitation is $18.5$ and the standard deviation of the annual precipitation amounts is 5.9. Let $x$ represent the annual precipitation in that city. Determine the standardized version of $x$ .

A) $z = \frac { x - 18.5 } { 5.9 }$
B) $x = \frac { z - 18.5 } { 5.9 }$
C) $z = \frac { x - 5.9 } { 18.5 }$
D) $z = - \frac { 18.5 } { 5.9 }$