Check GMAT Club Decision Tracker for the Latest School Decision Releases https://gmatclub.com/AppTrack
GMAT Club

 It is currently 25 Mar 2017, 09:06

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# A vending machine is designed to dispense 8 ounces of coffee

Author Message
TAGS:

### Hide Tags

Manager
Joined: 27 Feb 2010
Posts: 105
Location: Denver
Followers: 3

Kudos [?]: 362 [3] , given: 14

A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

27 Apr 2010, 06:21
3
KUDOS
26
This post was
BOOKMARKED
00:00

Difficulty:

25% (medium)

Question Stats:

75% (02:09) correct 25% (01:08) wrong based on 595 sessions

### HideShow timer Statistics

7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53

A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data above. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounces, how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

A. Four
B. Six
C. Nine
D. Ten
E. Eleven
[Reveal] Spoiler: OA
Math Expert
Joined: 02 Sep 2009
Posts: 37581
Followers: 7394

Kudos [?]: 99452 [17] , given: 11023

Re: Standard deviation of the mean? [#permalink]

### Show Tags

27 Apr 2010, 08:26
17
KUDOS
Expert's post
15
This post was
BOOKMARKED
zz0vlb wrote:
7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53

A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data above. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounces, how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

A. four
b. Six
c. Nine
d. Ten
e. Eleven

[Reveal] Spoiler:
e

Source: GMAT Prep

"Within 1.5 standard deviation of the mean" - means in the range {mean-1.5*sd; mean+1.5*sd} = {8.1-1.5*0.3; 8.1+1.5*0.3} = {7.65; 8.55}.

From the 12 listed amounts, only one (7.51) is out of this range and 11 are within this range.

_________________
Manager
Joined: 27 Feb 2010
Posts: 105
Location: Denver
Followers: 3

Kudos [?]: 362 [0], given: 14

Re: Standard deviation of the mean? [#permalink]

### Show Tags

27 Apr 2010, 09:43
got it bunuel. thanks. Your explanation is very clear.
Manager
Status: what we want to do, do it as soon as possible
Joined: 24 May 2010
Posts: 114
Location: Vietnam
WE 1: 5.0
Followers: 2

Kudos [?]: 63 [0], given: 315

Re: Standard deviation of the mean? [#permalink]

### Show Tags

03 Nov 2010, 09:07
Source: GMAT Prep[/quote]

"Within 1.5 standard deviation of the mean" - means in the range {mean-1.5*sd; mean+1.5*sd} = {8.1-1.5*0.3; 8.1+1.5*0.3} = {7.65; 8.55}.

From the 12 listed amounts, only one (7.51) is out of this range and 11 are within this range.

hi Bunuel,
I have not get clear why you take: 1.5*0.3
did i miss something? Please explain for me
_________________

Consider giving me kudos if you find my explanations helpful so i can learn how to express ideas to people more understandable.

Math Expert
Joined: 02 Sep 2009
Posts: 37581
Followers: 7394

Kudos [?]: 99452 [6] , given: 11023

Re: Standard deviation of the mean? [#permalink]

### Show Tags

03 Nov 2010, 09:19
6
KUDOS
Expert's post
2
This post was
BOOKMARKED
MICKEYXITIN wrote:
hi Bunuel,
I have not get clear why you take: 1.5*0.3
did i miss something? Please explain for me

We are given that SD=0.3 and mean=8.1. Question: how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

1.5 standard deviation equals to 1.5*SD=1.5*0.3=0.45, so "within 1.5 standard deviation of them mean" - means in the range {8.1-0.45; 8.1+0.45} = {7.65; 8.55}.

Hope it's clear.
_________________
Manager
Status: what we want to do, do it as soon as possible
Joined: 24 May 2010
Posts: 114
Location: Vietnam
WE 1: 5.0
Followers: 2

Kudos [?]: 63 [0], given: 315

Re: Standard deviation of the mean? [#permalink]

### Show Tags

03 Nov 2010, 10:23
Bunuel wrote:
MICKEYXITIN wrote:
hi Bunuel,
I have not get clear why you take: 1.5*0.3
did i miss something? Please explain for me

We are given that SD=0.3 and mean=8.1. Question: how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

1.5 standard deviation equals to 1.5*SD=1.5*0.3=0.45, so "within 1.5 standard deviation of them mean" - means in the range {8.1-0.45; 8.1+0.45} = {7.65; 8.55}.

Hope it's clear.

yes thanks Bunuel, i got it clear
_________________

Consider giving me kudos if you find my explanations helpful so i can learn how to express ideas to people more understandable.

Intern
Joined: 16 Aug 2012
Posts: 3
Followers: 0

Kudos [?]: 0 [0], given: 0

Re: Standard deviation of the mean? [#permalink]

### Show Tags

12 Nov 2012, 10:25
Bunuel wrote:
MICKEYXITIN wrote:
hi Bunuel,
I have not get clear why you take: 1.5*0.3
did i miss something? Please explain for me

We are given that SD=0.3 and mean=8.1. Question: how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

1.5 standard deviation equals to 1.5*SD=1.5*0.3=0.45, so "within 1.5 standard deviation of them mean" - means in the range {8.1-0.45; 8.1+0.45} = {7.65; 8.55}.

Hope it's clear.

Does the range include specifically numbers 7.65 and 8.55?
Math Expert
Joined: 02 Sep 2009
Posts: 37581
Followers: 7394

Kudos [?]: 99452 [0], given: 11023

Re: Standard deviation of the mean? [#permalink]

### Show Tags

12 Nov 2012, 10:37
NON wrote:
Bunuel wrote:
MICKEYXITIN wrote:
hi Bunuel,
I have not get clear why you take: 1.5*0.3
did i miss something? Please explain for me

We are given that SD=0.3 and mean=8.1. Question: how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

1.5 standard deviation equals to 1.5*SD=1.5*0.3=0.45, so "within 1.5 standard deviation of them mean" - means in the range {8.1-0.45; 8.1+0.45} = {7.65; 8.55}.

Hope it's clear.

Does the range include specifically numbers 7.65 and 8.55?

Luckily we don't need to worry about it for this question, though I'd say yes, the range has to be inclusive.
_________________
Senior Manager
Joined: 07 Sep 2010
Posts: 336
Followers: 7

Kudos [?]: 706 [0], given: 136

Re: Standard deviation of the mean? [#permalink]

### Show Tags

17 Sep 2013, 03:37
Bunuel wrote:
MICKEYXITIN wrote:
hi Bunuel,
I have not get clear why you take: 1.5*0.3
did i miss something? Please explain for me

We are given that SD=0.3 and mean=8.1. Question: how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

1.5 standard deviation equals to 1.5*SD=1.5*0.3=0.45, so "within 1.5 standard deviation of them mean" - means in the range {8.1-0.45; 8.1+0.45} = {7.65; 8.55}.

Hope it's clear.

Hello Bunuel,
Would you please clear one doubt.
The question states that "how many of the 12 listed amounts are within1.5 standard deviation of the mean? In this case, do we need to consider boundary values as well such as (7.65) and (8.55).
I mean, If the question had 7.65 value, then would we have considered 7.65 value ? i.e 7.65<= std deviation <= 8.55 is the range
Another doubt:
Question: how many of the 12 listed amounts are between 1.5 standard deviation of the mean?, and the answer choice had 7.65 as the value

Then, do we need to consider 7.65 value while answering ? I believe, not and 7.65< std deviation < 8.55 will be the range
_________________

+1 Kudos me, Help me unlocking GMAT Club Tests

Math Expert
Joined: 02 Sep 2009
Posts: 37581
Followers: 7394

Kudos [?]: 99452 [2] , given: 11023

Re: Standard deviation of the mean? [#permalink]

### Show Tags

17 Sep 2013, 03:41
2
KUDOS
Expert's post
5
This post was
BOOKMARKED
imhimanshu wrote:
Bunuel wrote:
MICKEYXITIN wrote:
hi Bunuel,
I have not get clear why you take: 1.5*0.3
did i miss something? Please explain for me

We are given that SD=0.3 and mean=8.1. Question: how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

1.5 standard deviation equals to 1.5*SD=1.5*0.3=0.45, so "within 1.5 standard deviation of them mean" - means in the range {8.1-0.45; 8.1+0.45} = {7.65; 8.55}.

Hope it's clear.

Hello Bunuel,
Would you please clear one doubt.
The question states that "how many of the 12 listed amounts are within1.5 standard deviation of the mean? In this case, do we need to consider boundary values as well such as (7.65) and (8.55).
I mean, If the question had 7.65 value, then would we have considered 7.65 value ? i.e 7.65<= std deviation <= 8.55 is the range
Another doubt:
Question: how many of the 12 listed amounts are between 1.5 standard deviation of the mean?, and the answer choice had 7.65 as the value

Then, do we need to consider 7.65 value while answering ? I believe, not and 7.65< std deviation < 8.55 will be the range

Please check the post just above yours: a-vending-machine-is-designed-to-dispense-8-ounces-of-coffee-93351.html#p1142674

Similar questions to practice:
arithmetic-mean-and-standard-deviation-of-a-certain-normal-104117.html
70-75-80-85-90-105-105-130-130-130-the-list-shown-consist-of-100361.html
for-a-certain-exam-a-score-of-58-was-2-standard-deviations-b-128661.html
a-certain-characteristic-in-a-large-population-has-a-143982.html
a-vending-machine-is-designed-to-dispense-8-ounces-of-coffee-93351.html
the-residents-of-town-x-participated-in-a-survey-83362.html
the-standard-deviation-of-a-normal-distribution-of-data-is-99221.html
the-mean-and-the-standard-deviation-of-the-8-numbers-shown-98248.html
_________________
GMAT Club Legend
Joined: 09 Sep 2013
Posts: 14407
Followers: 604

Kudos [?]: 174 [0], given: 0

Re: A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

03 Nov 2014, 09:00
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________
Senior Manager
Status: Math is psycho-logical
Joined: 07 Apr 2014
Posts: 442
Location: Netherlands
GMAT Date: 02-11-2015
WE: Psychology and Counseling (Other)
Followers: 2

Kudos [?]: 113 [1] , given: 169

A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

14 Jan 2015, 10:22
1
KUDOS
So:
M= 8.1
SD= 0.3
1.5 SD= 1 SD plus 1/2 SD, which is 0.3+0.15=0.45 SD.

Lets add and subtract 3SD or 0.45 from the M or 8.1:
8.1 - 0.45 = 7.65
8.1 + 0.45 = 8.55

So, we are looking for numbers in this range 7.65<numbers<8.55.

These are 11 of the 12 numbers, ANS E.
Intern
Joined: 21 Dec 2014
Posts: 15
Followers: 0

Kudos [?]: 4 [0], given: 2

### Show Tags

16 Mar 2015, 08:33
7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53

A vending machine is deisgned to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1000cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounce, how many of the 12 listed amounts are within 1.5 standard deviations of the mean

a) 4
b) 6
c) 9
d) 10
e) 11 (CORRECT)

11 is the correct answer, but why?
Math Expert
Joined: 02 Sep 2009
Posts: 37581
Followers: 7394

Kudos [?]: 99452 [0], given: 11023

Re: A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

16 Mar 2015, 08:43
Jeli13 wrote:
7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53

A vending machine is deisgned to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1000cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounce, how many of the 12 listed amounts are within 1.5 standard deviations of the mean

a) 4
b) 6
c) 9
d) 10
e) 11 (CORRECT)

11 is the correct answer, but why?

Merging topics.

_________________
Senior Manager
Joined: 15 Oct 2015
Posts: 377
Concentration: Finance, Strategy
GPA: 3.93
WE: Account Management (Education)
Followers: 4

Kudos [?]: 92 [0], given: 211

A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

18 Dec 2015, 05:09
I understand that this is an old post. But all the explanations above dont make sense to me. none really makes sense to me. The standard deviation question is one i havent got a good grip of. i solicit the help of experts like @veritasprep or if I'm lucky, GMATPrepNow
SVP
Joined: 08 Jul 2010
Posts: 1540
Location: India
GMAT: INSIGHT
WE: Education (Education)
Followers: 80

Kudos [?]: 1595 [1] , given: 44

Re: A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

22 Dec 2015, 01:18
1
KUDOS
Expert's post
zz0vlb wrote:
7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53

A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data above. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounces, how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

A. Four
B. Six
C. Nine
D. Ten
E. Eleven

Mean = 8.1
Standard Deviation = 0.3

within 1.5 standard deviation of the mean

i.e. 1.5 standard deviation ABOVE the mean = 8.1+1.5*0.3 = 8.55
and 1.5 standard deviation BELOW the mean = 8.1-1.5*0.3 = 7.65

Except first value 7.51, all other values are within the range hence, 11 values fall within 1.5 SD from Mean

_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

Feel free to give a Kudos if it is a useful post .

Senior Manager
Joined: 15 Oct 2015
Posts: 377
Concentration: Finance, Strategy
GPA: 3.93
WE: Account Management (Education)
Followers: 4

Kudos [?]: 92 [0], given: 211

Re: A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

22 Dec 2015, 03:32
GMATinsight wrote:
zz0vlb wrote:
7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53

A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data above. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounces, how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

A. Four
B. Six
C. Nine
D. Ten
E. Eleven

Mean = 8.1
Standard Deviation = 0.3

within 1.5 standard deviation of the mean

i.e. 1.5 standard deviation ABOVE the mean = 8.1+1.5*0.3 = 8.55
and 1.5 standard deviation BELOW the mean = 8.1-1.5*0.3 = 7.65

Except first value 7.51, all other values are within the range hence, 11 values fall within 1.5 SD from Mean

Thanks GMATinsight but why did you have multiply 1.5 with 0.3?
SVP
Joined: 08 Jul 2010
Posts: 1540
Location: India
GMAT: INSIGHT
WE: Education (Education)
Followers: 80

Kudos [?]: 1595 [0], given: 44

Re: A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

22 Dec 2015, 04:43
Nez wrote:
GMATinsight wrote:
zz0vlb wrote:
7.51 8.22 7.86 8.36
8.09 7.83 8.30 8.01
7.73 8.25 7.96 8.53

A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data above. If the 1000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounces, how many of the 12 listed amounts are within 1.5 standard deviation of the mean?

A. Four
B. Six
C. Nine
D. Ten
E. Eleven

Mean = 8.1
Standard Deviation = 0.3

within 1.5 standard deviation of the mean

i.e. 1.5 standard deviation ABOVE the mean = 8.1+1.5*0.3 = 8.55
and 1.5 standard deviation BELOW the mean = 8.1-1.5*0.3 = 7.65

Except first value 7.51, all other values are within the range hence, 11 values fall within 1.5 SD from Mean

Thanks GMATinsight but why did you have multiply 1.5 with 0.3?

1.5 standard deviation means 1.5*Standard Deviation

i.e. 1.5 standard deviation ABOVE the mean = 8.1+1.5*0.3 = 8.55
and 1.5 standard deviation BELOW the mean = 8.1-1.5*0.3 = 7.65

I hope this helps!
_________________

Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

Feel free to give a Kudos if it is a useful post .

Senior Manager
Joined: 15 Oct 2015
Posts: 377
Concentration: Finance, Strategy
GPA: 3.93
WE: Account Management (Education)
Followers: 4

Kudos [?]: 92 [0], given: 211

A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

25 Dec 2015, 10:24
Thanks GMATinsight.
You had good intentions, but that DID NOT HELP.
Manager
Joined: 03 Jan 2015
Posts: 91
Followers: 0

Kudos [?]: 31 [0], given: 146

Re: A vending machine is designed to dispense 8 ounces of coffee [#permalink]

### Show Tags

16 Mar 2016, 16:35
Nez wrote:
Thanks GMATinsight.
You had good intentions, but that DID NOT HELP.

I know you asked this question a while ago but what did you not understand? I would like to help you . Hope to hear from you soon.
Re: A vending machine is designed to dispense 8 ounces of coffee   [#permalink] 16 Mar 2016, 16:35

Go to page    1   2    Next  [ 24 posts ]

Similar topics Replies Last post
Similar
Topics:
2 A chemist mixes a 12-ounce solution that is 45% acid with 8 ounces of 2 19 Jan 2017, 07:58
1 A vending machine randomly dispenses four different types of fruit can 2 18 Nov 2015, 01:44
5 Carina has 100 ounces of coffee divided into 5- and 10-ounce packages. 6 30 Jun 2015, 04:40
Jamal can fill the vending machine in 45 minutes. When his 2 19 Mar 2012, 11:38
6 Arabica coffee costs \$0.4 per ounce while Robusta coffee 10 22 Nov 2007, 06:00
Display posts from previous: Sort by