## Que: Heights of trees in a large population have a distribution that is symmetric about.............

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### Que: Heights of trees in a large population have a distribution that is symmetric about.............

by [email protected] Revolution » Mon Jun 14, 2021 9:43 pm

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Que: Heights of trees in a large population have a distribution that is symmetric about the mean m. If 68 percent of the distribution lies within one standard deviation d of the mean, what percent of the distribution is greater than (m − d)?

A) 66%
B) 50%
C) 67%
D) 84%
E) 34% Math Revolution

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[Course] Starting $79 for on-demand and$60 for tutoring per hour and $390 only for Live Online. Email to : [email protected] Elite Legendary Member Posts: 3950 Joined: 24 Jul 2015 Location: Las Vegas, USA Thanked: 19 times Followed by:36 members ### Re: Que: Heights of trees in a large population have a distribution that is symmetric about............. by [email protected] Revolution » Wed Jun 16, 2021 7:44 pm Solution: We know that the distribution is symmetric about the mean. This is the concept of Normal distribution. Thus, the percent of the distribution equidistant from the mean on either side of it is the same. Let the percent of the distribution less than (m - d) be x%. Thus, the percent of the distribution more than (m + d) is also x%. Thus, we have => x% + 68% + x% = 100% => 2x = 32%, x=16% Thus, the percent of the distribution greater than (m − d) = 100% - x% =100% - 16% = 84%. D is the correct answer. Answer D Math Revolution The World's Most "Complete" GMAT Math Course! Score an excellent Q49-51 just like 70% of our students. [Free] Full on-demand course (7 days) - 100 hours of video lessons, 490 lesson topics, and 2,000 questions. [Course] Starting$79 for on-demand and $60 for tutoring per hour and$390 only for Live Online.
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