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#### Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here. # Eight hundred insects were weighed, and the resulting measur  Question banks Downloads My Bookmarks Reviews Important topics
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TAGS: Founder  Joined: 18 Apr 2015
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Eight hundred insects were weighed, and the resulting measur [#permalink]
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Eight hundred insects were weighed, and the resulting measurements, in milligrams, are summarized in the boxplot below.

Attachment: #GREexcercise Eight hundred insects were weighed.jpg [ 23.86 KiB | Viewed 4490 times ]

(a) What are the range, the three quartiles, and the interquartile range of the measurements?
(b) If the 80th percentile of the measurements is 130 milligrams, about how many measurements are between 126 milligrams and 130 milligrams?

[Reveal] Spoiler: OA
(a) range=41, Q_1 =114, Q_2 =118, Q_3 =126, interquartilerange=12 (b) 40 measurements

Math Review
Question: 5
Page: 297
Difficulty: medium

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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. Intern Joined: 02 Mar 2019
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Re: Eight hundred insects were weighed, and the resulting measur [#permalink]
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Hi,

Any explanations for the 2nd question?

Thanks! GRE Instructor Joined: 10 Apr 2015
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Re: Eight hundred insects were weighed, and the resulting measur [#permalink]
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Expert's post
Carcass wrote:
Eight hundred insects were weighed, and the resulting measurements, in milligrams, are summarized in the boxplot below.

Attachment:
The attachment #GREexcercise Eight hundred insects were weighed.jpg is no longer available

(a) What are the range, the three quartiles, and the interquartile range of the measurements?
(b) If the 80th percentile of the measurements is 130 milligrams, about how many measurements are between 126 milligrams and 130 milligrams?

[Reveal] Spoiler: OA
(a) range=41, Q_1 =114, Q_2 =118, Q_3 =126, interquartilerange=12 (b) 40 measurements

Math Review
Question: 5
Page: 297
Difficulty: medium

(a) What are the range, the three quartiles, and the interquartile range of the measurements?

Attachment: Eight hundred insects were weighed, and the resulting measurements1.png [ 12.69 KiB | Viewed 4342 times ]

Range = 146 - 105 = 41

Attachment: Eight hundred insects were weighed, and the resulting measurements2.png [ 12.95 KiB | Viewed 4337 times ]

The three quartiles are:
Q1 = 114, Q2 = 118, Q3 = 126

The interquartile range = (3rd quartile) - (1st quartile)
= 126 - 114
= 12

----------------------------------

(b) If the 80th percentile of the measurements is 130 milligrams, about how many measurements are between 126 milligrams and 130 milligrams?

80th percentile of the measurements is 130 milligrams
This means 80% of the measurements are LESS than 130 mg
80% of 800 = 640
So, 640 measurements are LESS than 130 mg

KEY CONCEPT: The 3rd quartile (Q3) is the same as the 75th percentile.
Q3 = 126
So, 75% of the measurements are LESS than 126 mg
75% of 800 = 600
So, 60 measurements are LESS than 126 mg

We get:
Attachment: Eight hundred insects were weighed, and the resulting measurements3.png [ 24.75 KiB | Viewed 4338 times ]

So, the number of measurements are BETWEEN 126 mg and 130 mg = 640 - 600 = 40

Cheers,
Brent
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Brent Hanneson – Creator of greenlighttestprep.com

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Re: Eight hundred insects were weighed, and the resulting measur [#permalink]
Interesting graph. What resource to use for practising such graph questions? Intern Joined: 02 Aug 2019
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Re: Eight hundred insects were weighed, and the resulting measur [#permalink]
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For b)

You can also notice that 126 = 75th percentile (Q3) and 130 = 80th percentile (given in the question).
So the difference between them (i.e. the numbers between them) is then equal to 5 percentiles and 5% of 800 = 40.
Founder  Joined: 18 Apr 2015
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Kudos [?]: 2268 , given: 8822

Re: Eight hundred insects were weighed, and the resulting measur [#permalink]
Expert's post
Interesting graph. What resource to use for practising such graph questions?

These https://greprepclub.com/forum/the-offic ... -8020.html

Regards
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