To determine the z-score of a raw data x, we have the formula below:
![z=\frac{rawdata-\operatorname{mean}}{sd}]()
Based on the question, our mean is 73 and standard deviation is 10.8.
a. x = 85 (raw data is 85)
Let's plug these values to the z formula.
![z=(85-73)/(10.8)=(12)/(10.8)\approx1.11](https://img.qammunity.org/2023/formulas/mathematics/high-school/to0rfloh1t3p4pwj1gaxmctmuionda2ij9.png)
We subtracted the mean from the raw data first (85 - 73 = 12). Then, we divide the results by 10.8. The result is 1.11.
Hence, equivalent z-score of x = 85 is 1.11.