Summer is Coming! Join the Game of Timers Competition to Win Epic Prizes. Registration is Open. Game starts Mon July 1st.

It is currently 18 Jul 2019, 23:23

Close

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
Your Progress

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.

Close

Request Expert Reply

Confirm Cancel

A certain airport security scanner designed to detect explosives in lu

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 56263
A certain airport security scanner designed to detect explosives in lu  [#permalink]

Show Tags

New post 03 Jul 2018, 11:15
00:00
A
B
C
D
E

Difficulty:

  75% (hard)

Question Stats:

47% (01:41) correct 53% (01:52) wrong based on 127 sessions

HideShow timer Statistics


A certain airport security scanner designed to detect explosives in luggage will alert the scanner’s operator whenever the piece of luggage passing under the scanner contains an explosive. The scanner will erroneously alert the operator for only one percent of the pieces of luggage that contain no explosives. Thus in ninety‑nine out of a hundred alerts explosives will actually be present.

The reasoning in the argument is flawed because the argument


(A) ignores the possibility of the scanner’s failing to signal an alert when the luggage does contain an explosive

(B) draws a general conclusion about reliability on the basis of a sample that is likely to be biased

(C) ignores the possibility of human error on the part of the scanner’s operator once the scanner has alerted him or her

(D) fails to acknowledge the possibility that the scanner will not be equally sensitive to all kinds of explosives

(E) substitutes one group for a different group in the statement of a percentage

_________________
Intern
Intern
avatar
B
Joined: 14 Oct 2017
Posts: 10
Re: A certain airport security scanner designed to detect explosives in lu  [#permalink]

Show Tags

New post 03 Jul 2018, 11:29
Answer is E? Incorrectly comparing no. Of erroneous alerts with no. Of pieces of luggage with no explosives


Sent from my iPhone using GMAT Club Forum mobile app
Board of Directors
User avatar
P
Status: QA & VA Forum Moderator
Joined: 11 Jun 2011
Posts: 4512
Location: India
GPA: 3.5
WE: Business Development (Commercial Banking)
GMAT ToolKit User
Re: A certain airport security scanner designed to detect explosives in lu  [#permalink]

Show Tags

New post 03 Jul 2018, 11:43
gilltaurus wrote:
Answer is E? Incorrectly comparing no. Of erroneous alerts with no. Of pieces of luggage with no explosives


Sent from my iPhone using GMAT Club Forum mobile app


With the same opinion, must be (E)

Quote:
A certain airport security scanner designed to detect explosives in luggage will alert the scanner’s operator whenever the piece of luggage passing under the scanner contains an explosive. The scanner will erroneously alert the operator for only one percent of the pieces of luggage that contain no explosives. Thus in ninety‑nine out of a hundred alerts explosives will actually be present.


Compares percentage error in one statement to the actual number of alerts !!
_________________
Thanks and Regards

Abhishek....

PLEASE FOLLOW THE RULES FOR POSTING IN QA AND VA FORUM AND USE SEARCH FUNCTION BEFORE POSTING NEW QUESTIONS

How to use Search Function in GMAT Club | Rules for Posting in QA forum | Writing Mathematical Formulas |Rules for Posting in VA forum | Request Expert's Reply ( VA Forum Only )
Senior Manager
Senior Manager
User avatar
P
Joined: 07 Dec 2017
Posts: 317
GMAT 1: 660 Q50 V30
Reviews Badge
Re: A certain airport security scanner designed to detect explosives in lu  [#permalink]

Show Tags

New post 10 Jul 2018, 18:59
IMO ANSWER E:

This is how: acc to the premise, the scanner will show 1% of false positive for all non-explosive luggage

Let's take nos: 100 non-explosive pieces of luggage, the scanner will result in 1 case of False positive but based
on this information, we cant deduce the accuracy for all the luggage which contain explosives as we have
info available for the accuracy of false + for non-explosive Luggage
GMAT Club Bot
Re: A certain airport security scanner designed to detect explosives in lu   [#permalink] 10 Jul 2018, 18:59
Display posts from previous: Sort by

A certain airport security scanner designed to detect explosives in lu

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne