PLEASE ANSWER ASAP

Question

Which grade is better: A 78 on a test whose mean is 72 and standard deviation is 6.2, or an 83 on a test whose mean is 77 and standard deviation is 8.4? Justify your answer 

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Answer 1

z = (78 - 72) / 6.2, z = 0.967771935

z = (83 - 77) / 8.4, z = 0.714285714