High School

The scores on a mathematics exam have a mean of 77 and a standard deviation of 8.

Find the [tex]$x$[/tex]-value that corresponds to the [tex]$z$[/tex]-score 2.575.

Use the formula: [tex]$x = \mu + z \sigma$[/tex]

A. 56.4
B. 79.6
C. 85.0
D. 97.6

Answer :

To find the [tex]\(x\)[/tex]-value that corresponds to the [tex]\(z\)[/tex]-score of 2.575, we use the formula:

[tex]\[ x = \mu + z\sigma \][/tex]

Where:
- [tex]\( \mu \)[/tex] is the mean of the scores
- [tex]\( z \)[/tex] is the [tex]\( z \)[/tex]-score
- [tex]\( \sigma \)[/tex] is the standard deviation

Given:
- The mean ([tex]\(\mu\)[/tex]) is 77
- The standard deviation ([tex]\(\sigma\)[/tex]) is 8
- The [tex]\( z \)[/tex]-score is 2.575

Substitute these values into the formula:

[tex]\[ x = 77 + (2.575 \times 8) \][/tex]

First, calculate the product of the [tex]\( z \)[/tex]-score and the standard deviation:

[tex]\[ 2.575 \times 8 = 20.6 \][/tex]

Now, add this result to the mean:

[tex]\[ x = 77 + 20.6 = 97.6 \][/tex]

Therefore, the [tex]\(x\)[/tex]-value that corresponds to the [tex]\(z\)[/tex]-score 2.575 is 97.6. So, the correct answer is:

d. 97.6

Other Questions