I scored an 85 percent on my exam. The mean score for that quiz was -83.73 and standard deviation was -24.23 what is the z score for this exam?
I assume the mean and SD are not negative.
Z = (score-mean)/SD
Insert values and solve for Z.
I'm a little confused on how to do it and then convert it into a percentage when I do work it out it comes to a huge number. I don't know to do anything after that . I get .31295738
To find the z-score, which represents how many standard deviations your score is above or below the mean, you need to use the formula:
z = (X - μ) / σ
where:
- z is the z-score
- X is your score
- μ is the mean
- σ is the standard deviation
In this case:
- Your score (X) is 85%
- The mean (μ) is -83.73 (based on the information you provided, it seems unusual for the mean to be negative and the standard deviation to have decimals, so please double-check those values)
- The standard deviation (σ) is -24.23
Now, substituting these values into the formula, we get:
z = (85 - (-83.73)) / -24.23
Simplifying further:
z = 168.73 / -24.23
z ≈ -6.96
Therefore, the approximate z-score for your exam is -6.96.