The average score on the statistics quiz was a 70,and there was a standard deviation of 10 points.If Enrique had a z-score of -1.0,his raw score would be ______ and his percentile rank would be ______.
A)40;2%
B)50;16%
C)60;16%
D)60;34%

Question

Quizplus · Accepted Answer

To find the raw score, we use the formula:

z-score = (raw score - mean) / standard deviation

Substituting the given values, we get:

1.0 = (raw score - 70) / 10

Solving for the raw score, we get:

raw score = 70 + 10(1.0) = 80

To find the percentile rank, we use a z-table and look for the area to the left of the z-score. From the table, we find that the area to the left of a z-score of 1.0 is 0.8413, or 84.13%.

However, we need to find the percentile rank below the score, so we subtract the area from 1 and convert to a percentage:

percentile rank = (1 - 0.8413) x 100% ≈ 15.87%

Therefore, the best choice is C) 60; 16%.

The Average Score on the Statistics Quiz Was a 70,and