Final answer:
To find the mean (μ) for a test where a student scored 230 with a z-score of 3.5 and a standard deviation (σ) of 18, we rearrange the score calculation formula: μ = 230 - (3.5)(18), which gives us a mean of 167.
Step-by-step explanation:
To find the mean of the test scores when a student scored 230 with a z-score of 3.5 given the standard deviation is 18, we use the formula for calculating a score from a z-score:
x = μ + (z)(σ)
Where:
- x is the raw score
- μ is the mean
- z is the z-score
- σ is the standard deviation
We rearrange the formula to solve for the mean (μ):
μ = x - (z)(σ)
Substituting the given values:
μ = 230 - (3.5)(18)
μ = 230 - 63
μ = 167
The mean for the test is 167.