Question 1194419
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The z score formula is
z = (x - mu)/sigma
where,
x = raw score
mu = mean
sigma = standard deviation


I'll treat each xbar as mu, and each s as sigma


For part A, we have
x = 43
mu = 40
sigma = 3


So,
z = (x - mu)/sigma
z = (43-40)/3
z = 3/3
z = 1
which is the z score to part A.


A z score of 1 means we're exactly 1 standard deviation above the mean.
Positive z scores are above the mean, while negative z scores are below the mean.


For part B, we have this z score
z = (x - mu)/sigma
z = (75 - 72)/5
z = 3/5
z = 0.6


We can see that the z score in part A is larger; therefore, the exam grade in class A is in a better relative position to the entire class.


Answer: Choice A.
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