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 .

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:

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

the mistake in the pattern is that :

b. the decimal point was moved one too many place values each time

the correct pattern could be made by :

b. moving the decimal point to the right the same numbers of place values as the exponents