Answer:
His actual score is 15
Step-by-step explanation:
Here, we are interested in calculating Wayne’s actual score on the ACT
when we say the scores have being standardized, it means the score was reported in terms of the z-score and not the initial raw scores.
Now, mathematically, for the scores to have a negative z-score, it means it is actually below the mean.
The formula for the z-score or standard score is given below;
z-score = (x - mean)/SD
where in this case, x = ? which is the score we are looking for , z-score = -0.5 , mean score = 18 and standard deviation of the scores = 6
So, substituting these values into the z-score equation, we have;
-0.5 = (x-18)/6
x-18 = 6(-0.5)
x -18 = -3
x = -3 + 18
x = 15
