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) $z = - \frac { 18.5 } { 5.9 }$

Question

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) $z = - \frac { 18.5 } { 5.9 }$

Quizplus · Accepted Answer

The standardized version of a variable $x$ is given by $z = \frac { x - \mu } { \sigma }$, where $\mu$ is the mean and $\sigma$ is the standard deviation. Here, $\mu = 18.5$ and $\sigma = 5.9$, so the correct formula is $z = \frac { x - 18.5 } { 5.9 }$.

A Meteorological Office Keeps Records of the Annual Precipitation in Different