Question 1193047
i would say B.
the formula for a z-score of an individual element is z = (x - m) / sd
the formula for a z-score of the mean of a sample of n elements is z = (x - m) / (sd / sqrt(n)).
z is the z-score
x is the raw score
m is the mean
sd is the standard deviation of an individual element in the distribution of elements.
(sd / sqrt(n)) is the standard deviation of the sample means in a distribution of sample means.
here's a reference on the subject.
<a href = "https://onlinestatbook.com/2/sampling_distributions/samp_dist_mean.html" target = "_blank">https://onlinestatbook.com/2/sampling_distributions/samp_dist_mean.html</a>
here's another.
<a href = "http://matcmath.org/textbooks/engineeringstats/distribution-of-sample-means/" target = "_blank">http://matcmath.org/textbooks/engineeringstats/distribution-of-sample-means/</a>