On a recent English exam,scores averaged 84 points.If 41% of scores fell below 70 points,find an approximate standard deviation (assuming the Normal model is appropriate).
A)60.87
B)-69.57
C)-669.57
D)34.44
E)28.7

Question

Quizplus · Accepted Answer

The correct answer is A because the standard deviation is approximately 60.87 points. This can be calculated using the formula: standard deviation = (range / 4) * (1 - (percentage of scores below 70 / 100)). In this case, the range is 100 - 70 = 30 points, and the percentage of scores below 70 is 41%. So, the standard deviation is approximately (30 / 4) * (1 - (41 / 100)) = 60.87 points.

On a Recent English Exam,scores Averaged 84 Points