"A recent study of Greek children estimated that the average weight of a 10-year old boy was 81.57 pounds with a standard deviation of 17.41 pounds (Papadimitriou et al., 2006)." What percentage of boys weigh between 70 and 90 pounds?
A) 6.10%
B) 24.54%
C) 42.98%
D) 68.44%

Question

Quizplus · Accepted Answer

First, we need to find the z-scores for the given weights:

z1 = (70-81.57)/17.41 = -0.66 
z2 = (90-81.57)/17.41 = 0.48

Using a standard normal distribution table or calculator, we can find the area under the curve between these z-scores:

area = P(-0.66 < z < 0.48)

area = P(z < 0.48) - P(z < -0.66)

area = 0.6844 - 0.2614

area = 0.423

Converting the decimal to a percentage, we get:

percentage = 42.98%

Therefore, the correct answer is (C) 42.98%.

"A Recent Study of Greek Children Estimated That the Average