A sample data set has a mean of 122.3 and a standard deviation of 18.5. Convert a score of 168.4 to a z score and determine if the score is “usual” or “unusual.”

Respuesta :

Answer:

[tex]Z=2.49[/tex] and this Z-score is “unusual.”

Step-by-step explanation:

To calculate the Z score use the following formula

[tex]Z=\frac{x-\mu}{\sigma}[/tex]

Where

μ is the average

[tex]\sigma[/tex] is the standard deviation

x is the data to which we will calculate the z-score

In this case

[tex]\mu = 122.3\\\\\sigma= 18.5\\\\x =168.4[/tex]

So

[tex]Z=\frac{168.4-122.3}{18.5}[/tex]

[tex]Z=2.49[/tex]

A z-score is unusual if [tex]Z> 2[/tex] or [tex]Z < -2[/tex]

Finally

[tex]Z=2.49[/tex] and this Z-score is “unusual.”