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The World Health Organization (WHO) has produced a comprehensive set of growth standards for children. These standards are based on studies of children living in 6 nations on 5 continents under optimal conditions with respect to health and nutrition. The table displays the percentil distribution of height, in centimeters, at 3-month intervals, for boys ages 2 through 5 according to the WHO model. In a model population -- a large population of boys ages 2 through 5 that conforms to the WHO growth standards -- for n = 3, 15, 50, 85, and 97, nth percentile in height for a given age is the unique height among boys of that age that is greater than or equal to n percent, and less than or equal to (100- n) percent, of heights of boys of that age.


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by DavidG@VeritasPrep » Wed Sep 13, 2017 6:37 am
Consider an individual boy from a model population. Suppose that from age 2 through age 5, this boy's weight is at the 50th percentile for his height and his height is at the 50th percentile for his age. Which one of the following statements must be true of the boy at age 5 years 0 months?

A) His age is at the 50th percentile for his height.
B) His weight is at the 50th percentile for his age.
C) His height is at the 50th percentile for his weight.
D) His weight is approximately 150% of his weight at age 2 years 0 months.
E) His weight is approximately 200% of his weight at age 2 years 0 months.

If this boy is 50th percentile height for his age when he's five, we can see that he'll be 110 cm. If his weight is 50th percentile for his height, then we can use the weight-for-height graph and find the weight that corresponds to 110 for the yellow line. It looks to be about 18kg.

If this boy is 50th percentile height for his age when he's two, we can see that he'll be 87 cm. If his weight is 50th percentile for his height, then we can use the weight-for-height graph and find the weight that corresponds to 87 for the yellow line. It looks to be about 12kg.

18 is 150% of 12. (18/12) * 100 =150. So the answer is D.
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by RBBmba@2014 » Mon Sep 18, 2017 11:13 pm
@ Dave: Why B is wrong in the first Qs ?
Last edited by RBBmba@2014 on Mon Sep 18, 2017 11:18 pm, edited 1 time in total.

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by RBBmba@2014 » Mon Sep 18, 2017 11:16 pm
@Anaira Mitch: Can you please publish the OAs through "Spoiler" for the 2nd & 3rd Qs ?