College

The average class size this semester in the business school of a particular university is 38.1 students with a standard deviation of 12.9 students. The z-score for a class with 21 students is ________.

Answer :

Answer:

The z-score for a a class with 21 students is -1.33.

Step-by-step explanation:

The z-score of a raw X is computed by subtracting the mean of a distribution from the raw score X and dividing the result by the standard deviation of the distribution.

The z-scores are standardized scores and follow a Standard normal distribution.

Given:

μ = 38.1

σ = 12.9

X = 21

Compute the z-score for the raw score X as follows:

[tex]z=\frac{X-\mu}{\sigma} =\frac{21-38.1}{12.9} =-1.32558\approx-1.33[/tex]

Thus, the z-score for a a class with 21 students is -1.33.

The z-score for a class with 21 students is approximately -1.33.

To find the z-score for a class with 21 students, given the average class size (mean) of 38.1 students and a standard deviation of 12.9 students, we use the formula:

Z = (X - μ) / σ, where:

X is the value for which we are finding the z-score (in this case, 21 students),μ is the mean (38.1 students), andσ is the standard deviation (12.9 students).

Substituting these values into the formula gives:

Z = (21 - 38.1) / 12.9

Z = -17.1 / 12.9

Z ≈ -1.33

Therefore, the z-score for a class with 21 students is approximately -1.33.