Calculating a z-score
On an exam with a mean of 70 and a standard deviation of 5, a student scores 85. What is her z-score?
Answer B: explanation for every choice
A
This divides by 10 instead of the standard deviation.
B
Correct. z = (85 − 70)/5 = 3.
C
5 is the standard deviation.
D
15 is the raw difference from the mean.
Takeawayz = (x − μ)/σ.
Equation usedz-score
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