IQ scores have a mean of 100 and a standard deviation of 15. Kate has an IQ of 121. (a) What is the difference between Kate's IQ and the mean

Respuesta :

Answer:

(a) The difference between Kate's IQ and the mean is 21

(b) The z score is 1.4

Step-by-step explanation:

Here is the complete question:

IQ scores have a mean of 100 and a standard deviation of 15. Kate has an IQ of 121. (a) What is the difference between Kate's IQ and the mean (b) Convert Kate's IQ score to a z score.

Step-by-step explanation:

(a) To determine the difference between Kate's IQ and the mean, this can be done by subtracting the mean from Kate's IQ.

Mean = 100

Kate's IQ = 121

Difference between Kate's IQ and the mean = 121 - 100 = 21

Hence, the difference between Kate's IQ and the mean is 21.

(b) To convert Kate's IQ score to a z score,

z score is given by the formula

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

Where [tex]x[/tex] is the score

[tex]\mu[/tex] is the mean

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

From the question,

[tex]x[/tex] = 121

[tex]\mu[/tex] = 100

[tex]\sigma[/tex] = 15

Then, the z score is

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

[tex]z =\frac{121 - 100}{15}[/tex]

[tex]z =\frac{21}{15}[/tex]

[tex]z =\frac{7}{5}[/tex]

z = 1.4

Hence, the z score is 1.4.