Question

Finding missing o in z score

Answer 1

By formula,

`\begin{gathered} Z=(X-\mu)/(\sigma) \\ \text{Where Z=2.15 , X }=\text{ 479, }\mu=436,\text{ and }\sigma=? \end{gathered}`

Substituting these values into the above formula, we get

`\begin{gathered} 2.15=(479-436)/(\sigma) \\ \text{Cross multiplying, we get} \\ 2.15\sigma=43 \\ \text{Dividing both sides by 2.15, we get} \\ \sigma=(43)/(2.15)=20\text{ }\approx\text{ 20.0 (to one decimal place)} \end{gathered}`

The correct answer is 20.0 ( to one decimal place)