Question

Scores of 281 students on an exam were normally distributed with the mean 79 and the standard deviation of 6. Using the "68-95-99.7" rule, estimate how many students score above 91 O 15 O 14 Not enough information to answer the question None of the given numerical values is correct 10

Answer 1

empirical rule graphs can be constructed as follows

50% 500 2.35% 13.5% 34% 34% 13.5% 2.35% 68% 9530 99.700

from above graph it is clear that above 2 standard deviation, on right side, information is 2.35 %

now above 79+2*6 = 91 it will be

2.35% X 281

6.6035

7 approx .

option sixth is correct.

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