Questions: Scores on a test have a mean of 66 and a standard deviation of 9. Michelle has a score of 57. Convert Michelle's score to a z-score.
A. 1
B. -1
C. -9
D. 9
Transcript text: Scores on a test have a mean of 66 and a standard deviation of 9 . Michelle has a score of 57 . Convert Michelle's score to a $z$-score.
A. 1
B. -1
C. -9
D. 9