Question

How do u figure out what x is in a normal distribution question

Answer 1

Data:

• Mean (μ) = 50

,

• Standard deviation (σ) = 3

,

• P( ,x >=47 ,)

Procedure:

1. Since μ = 50 and σ = 3:

`P(x\le47)=P(X-\mu<47-50)=P((x-\mu)/(\sigma)<(47-50)/(3))`
`Z=(x-\mu)/(\sigma)`
`(47-50)/(3)=-1`

2. Replacing the values:

`P(x\le47)=P(Z\le-1)`

With this, we do not have to figure out what x is.

3. Using the standard normal table:

`P(Z\le-1)=0.1587\approx0.16`

Answer: A. 0.16