 It is currently 18 Jan 2020, 10:36 ### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

#### Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here. # The ﬁgure above shows a normal distribution with mean m and  Question banks Downloads My Bookmarks Reviews Important topics
Author Message
TAGS:
Founder  Joined: 18 Apr 2015
Posts: 9336
Followers: 193

Kudos [?]: 2268 , given: 8822

The ﬁgure above shows a normal distribution with mean m and [#permalink]
Expert's post
Attachment: #GREexcercise The ﬁgure above shows a normal distribution.jpg [ 21.44 KiB | Viewed 2417 times ]

The ﬁgure above shows a normal distribution with mean m and standard deviation d, including approximate percents of the distribution corresponding to the six regions shown.

Suppose the heights of a population of 3,000 adult penguins are approximately normally distributed with a mean of 65 centimeters and a standard deviation of 5 centimeters.

(a) Approximately how many of the adult penguins are between 65 centimeters and 75 centimeters tall?
(b) If an adult penguin is chosen at random from the population, approximately what is the probability that the penguin’s height will be less than 60 centimeters? Give your answer to the nearest 0.05.

[Reveal] Spoiler: OA
(a) 1,440 (b) 0.15

Math Review
Question: 16
Page: 298
Difficulty: medium

_________________

Need Practice? 20 Free GRE Quant Tests available for free with 20 Kudos
GRE Prep Club Members of the Month: Each member of the month will get three months free access of GRE Prep Club tests. GRE Instructor Joined: 10 Apr 2015
Posts: 2672
Followers: 101

Kudos [?]: 2954  , given: 45

Re: The ﬁgure above shows a normal distribution with mean m and [#permalink]
1
KUDOS
Expert's post
Carcass wrote:
Attachment:
#GREexcercise The ﬁgure above shows a normal distribution.jpg

The ﬁgure above shows a normal distribution with mean m and standard deviation d, including approximate percents of the distribution corresponding to the six regions shown.

Suppose the heights of a population of 3,000 adult penguins are approximately normally distributed with a mean of 65 centimeters and a standard deviation of 5 centimeters.

(a) Approximately how many of the adult penguins are between 65 centimeters and 75 centimeters tall?
(b) If an adult penguin is chosen at random from the population, approximately what is the probability that the penguin’s height will be less than 60 centimeters? Give your answer to the nearest 0.05.

[Reveal] Spoiler: OA
(a) 1,440 (b) 0.15 GIVEN: The heights are approximately normally distributed with a mean of 65 centimeters and a standard deviation of 5 centimeters.
Let's add this information to the diagram to get: (a) Approximately how many of the adult penguins are between 65 centimeters and 75 centimeters tall?
From the diagram... ...we can see that 48% of the heights are between 65 centimeters and 75 centimeters.
So, the NUMBER of the penguins between 65 cm and 75 cm = 48% of 3000 = 1440

----------------------------------------------------------
(b) If an adult penguin is chosen at random from the population, approximately what is the probability that the penguin’s height will be less than 60 centimeters? Give your answer to the nearest 0.05
From the diagram... ...we can see that 16% of the heights are less than 60 centimeters.
So, P(chosen penguin is less than 60 cm tall) = 16% = 0.16

IMPORTANT: the question asks for the answer to be to the nearest 0.05
So, possible answers are: 0.05, 0.10, 0.15, 0.20, 0.25, 0.30,...etc
So, 0.15 is the closest to 0.16

Cheers,
Brent
_________________

Brent Hanneson – Creator of greenlighttestprep.com Re: The ﬁgure above shows a normal distribution with mean m and   [#permalink] 02 Jun 2019, 09:52
Display posts from previous: Sort by

# The ﬁgure above shows a normal distribution with mean m and  Question banks Downloads My Bookmarks Reviews Important topics  Powered by phpBB © phpBB Group Kindly note that the GRE® test is a registered trademark of the Educational Testing Service®, and this site has neither been reviewed nor endorsed by ETS®.