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.
