A normal distribution of data has a mean of 90 and a standard deviation of 18. What is the approximate z-score for the value 64?
–3.6
–1.4
1.4
3.6

correct option B)

Step-by-step explanation:

We have , A normal distribution of data has a mean of 90 and a standard deviation of 18. We need to find that What is the approximate z-score for the value 64 . Let's find out :

We have ,

(Mean) μ=90

(Standard deviation ) σ=18

X = 64

We know that Z = ( X − μ )/σ :

⇒  Z = ( X − μ )/σ

⇒  Z = ( 64 − 90 )/18

⇒  Z = ( -26 )/18

⇒  Z = -1.44

On rounding off :

⇒  Z = -1.4

Therefore, the approximate z-score for the value 64 is  Z = -1.4 . correct option B)

-1.4

Step-by-step explanation: