Todd takes an achievement test that yields standard scores.The mean of the test scores is 200, and the standard deviation is 50.If Todd does better than 84% of the students in his age-group who take the test, his standard score is:
A)150
B)200
C)250
D)300

Question

Quizplus · Accepted Answer

To find Todd's standard score, we need to use the inverse normal distribution table.

- We know that Todd does better than 84% of the students, so the area to the left of his score on the standard normal distribution is 0.84. 
- We can use the inverse normal distribution table to find the z-score that corresponds to an area of 0.84: z = 1.04. 
- Now we can use the formula to convert z-score to a standard score:

Standard score = (z-score x standard deviation) + mean
Standard score = (1.04 x 50) + 200
Standard score = 250

Therefore, the answer is C.

Todd Takes an Achievement Test That Yields Standard Scores