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# Biometric access-control systems those using fingerprints,

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Biometric access-control systems those using fingerprints, [#permalink]

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09 Aug 2008, 00:13
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Biometric access-control systems—those using fingerprints, voice prints, etc., to regulate admittance to restricted areas—work by degrees of similarity, not by identity. After all, even the same finger will rarely leave exactly identical prints. Such systems can be adjusted to minimize refusals of access to legitimate access-seekers. Such adjustments, however, increase the likelihood of admitting impostors.
Which of the following conclusions is most strongly supported by the information above?
(A) If a biometric access-control system were made to work by identity, it would not produce any correct admittance decisions.
(B) If a biometric access-control system reliably prevents impostors from being admitted, it will sometimes turn away legitimate access-seekers.
(C) Biometric access-control systems are appropriate only in situations in which admittance of impostors is less of a problem than is mistaken refusal of access.
(D) Nonbiometric access-control systems—based, for example, on numerical codes—are less likely than biometric ones to admit impostors.
(E) Anyone choosing an access-control system should base the choice solely on the ratio of false refusals to false admittances.

Do post in the explanations !!!
OA given is not at all convincing
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09 Aug 2008, 00:44
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Biometric access-control systems—those using fingerprints, voice prints, etc., to regulate admittance to restricted areas—work by degrees of similarity, not by identity. After all, even the same finger will rarely leave exactly identical prints. Such systems can be adjusted to minimize refusals of access to legitimate access-seekers. Such adjustments, however, increase the likelihood of admitting impostors.
Which of the following conclusions is most strongly supported by the information above?
(A) If a biometric access-control system were made to work by identity, it would not produce any correct admittance decisions. This is a very strong statement. Notice- "it would not produce". The premise says that they do not work by identity, but, we do not know wheather it will produce correct results or not if it works by identity.
(B) If a biometric access-control system reliably prevents impostors from being admitted, it will sometimes turn away legitimate access-seekers. - According to the premise, if the system is adjusted to minimize legitimate refusals and increase the likelihood of admitting imposters, the converse should also be true. This is stated in this answer choice.
(C) Biometric access-control systems are appropriate only in situations in which admittance of impostors is less of a problem than is mistaken refusal of access.- The systems can be appropriate in situations where admittance of imposters can be a major problem also. One can do this by the adjusting the systems. Also, notice "only" here which signifies the strength of the statement.
(D) Nonbiometric access-control systems—based, for example, on numerical codes—are less likely than biometric ones to admit impostors. This is irrelevant, the non-biometric access is out of scope of the argument.
(E) Anyone choosing an access-control system should base the choice solely on the ratio of false refusals to false admittances. This is also irrelevant. Choosing based on the ratio of refusal to false admittance is out of scope.
IMO, it is (B). What is OA?
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09 Aug 2008, 00:59
imo b

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09 Aug 2008, 01:04
spriya wrote:
Biometric access-control systems—those using fingerprints, voice prints, etc., to regulate admittance to restricted areas—work by degrees of similarity, not by identity. After all, even the same finger will rarely leave exactly identical prints. Such systems can be adjusted to minimize refusals of access to legitimate access-seekers. Such adjustments, however, increase the likelihood of admitting impostors.
Which of the following conclusions is most strongly supported by the information above?
(A) If a biometric access-control system were made to work by identity, it would not produce any correct admittance decisions.
(B) If a biometric access-control system reliably prevents impostors from being admitted, it will sometimes turn away legitimate access-seekers.
(C) Biometric access-control systems are appropriate only in situations in which admittance of impostors is less of a problem than is mistaken refusal of access.
(D) Nonbiometric access-control systems—based, for example, on numerical codes—are less likely than biometric ones to admit impostors.
(E) Anyone choosing an access-control system should base the choice solely on the ratio of false refusals to false admittances.

Do post in the explanations !!!
OA given is not at all convincing

I second B as well.

IF the system is adjusted, something will happen. C talks about where the system can be used after adjustments. I stick to the IF and choose B. Rest of the choices are losers.
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09 Aug 2008, 10:52
leonidas wrote:
Biometric access-control systems—those using fingerprints, voice prints, etc., to regulate admittance to restricted areas—work by degrees of similarity, not by identity. After all, even the same finger will rarely leave exactly identical prints. Such systems can be adjusted to minimize refusals of access to legitimate access-seekers. Such adjustments, however, increase the likelihood of admitting impostors.
Which of the following conclusions is most strongly supported by the information above?
(A) If a biometric access-control system were made to work by identity, it would not produce any correct admittance decisions. This is a very strong statement. Notice- "it would not produce". The premise says that they do not work by identity, but, we do not know wheather it will produce correct results or not if it works by identity.
(B) If a biometric access-control system reliably prevents impostors from being admitted, it will sometimes turn away legitimate access-seekers. - According to the premise, if the system is adjusted to minimize legitimate refusals and increase the likelihood of admitting imposters, the converse should also be true. This is stated in this answer choice.
(C) Biometric access-control systems are appropriate only in situations in which admittance of impostors is less of a problem than is mistaken refusal of access.- The systems can be appropriate in situations where admittance of imposters can be a major problem also. One can do this by the adjusting the systems. Also, notice "only" here which signifies the strength of the statement.
(D) Nonbiometric access-control systems—based, for example, on numerical codes—are less likely than biometric ones to admit impostors. This is irrelevant, the non-biometric access is out of scope of the argument.
(E) Anyone choosing an access-control system should base the choice solely on the ratio of false refusals to false admittances. This is also irrelevant. Choosing based on the ratio of refusal to false admittance is out of scope.
IMO, it is (B). What is OA?

Agreed on B but one query on cause and effect!!
if x causes y
can we say when not y occurs not x is there

choice :
If a biometric access-control system reliably prevents impostors from being admitted, it will sometimes turn away legitimate access-seekers.

im usually confused in this relation kindly shed some light on this
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09 Aug 2008, 11:34
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can we say when not y occurs not x is there
choice :
If a biometric access-control system reliably prevents impostors from being admitted, it will sometimes turn away legitimate access-seekers.
---------------------------------------------------------------------------------------------------------------
Usually, for cause and effect, it is helpful when we dissect the argument apart:
A= Decrease in refusal to real users.

In this case, A causes B (Given from the stem) We can not deny this.

The possible variations are:
1) Increase in imposter admission -> decrease in refusal to real users (Given)
2) Increase in refusal to real users-> decrease in imposter admission (Derived statement that must be true based on given)

The answer choice actually reiterates 2). Hence B.
For Cause and effect arguments, it is good to write a couple of words with increase and decrease arrows and understand the relationship prior to reading the answer choices. This greatly helps (atleast to me), to eliminate the incorect ones. This question might not warranty a diagram or notes, however, some of the complex cause and effect arguments (similar to puzzles) might do.
Hope this helps!!!!!!
_________________

To find what you seek in the road of life, the best proverb of all is that which says:
"Leave no stone unturned."
-Edward Bulwer Lytton

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09 Aug 2008, 17:52
leonidas wrote:
can we say when not y occurs not x is there
choice :
If a biometric access-control system reliably prevents impostors from being admitted, it will sometimes turn away legitimate access-seekers.
---------------------------------------------------------------------------------------------------------------
Usually, for cause and effect, it is helpful when we dissect the argument apart:
A= Decrease in refusal to real users.

In this case, A causes B (Given from the stem) We can not deny this.

The possible variations are:
1) Increase in imposter admission -> decrease in refusal to real users (Given)
2) Increase in refusal to real users-> decrease in imposter admission (Derived statement that must be true based on given)

The answer choice actually reiterates 2). Hence B.
For Cause and effect arguments, it is good to write a couple of words with increase and decrease arrows and understand the relationship prior to reading the answer choices. This greatly helps (atleast to me), to eliminate the incorect ones. This question might not warranty a diagram or notes, however, some of the complex cause and effect arguments (similar to puzzles) might do.
Hope this helps!!!!!!

+1 for
this a good explanation.
its good to break the argument and derive the relationship between cause and effect.
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Re: Biometric access-control systems those using fingerprints, [#permalink]

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07 May 2016, 09:33
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Re: Biometric access-control systems those using fingerprints, [#permalink]

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23 Jul 2016, 07:10
I fail to understand the argument
can someone explain in simple words please?

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Re: Biometric access-control systems those using fingerprints, [#permalink]

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23 Jul 2016, 08:42
chetan2u could u pls help with this one. Seems tricky

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Biometric access-control systems those using fingerprints, [#permalink]

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24 Jul 2016, 15:09
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Expert's post
paidlukkha wrote:
I fail to understand the argument
can someone explain in simple words please?

rahulkashyap wrote:
chetan2u could u pls help with this one. Seems tricky

Posted from my mobile device

I am trying to generalize all similar testing problems.

There are 4 possible responses from any such control system:

1. True positive ( someone is imposter and identifying him as imposter)
2. False positive ( someone is NOT an imposter, yet identifying him as imposter)
3. True negative (someone is NOT an imposter, and identifying him as NOT an imposter)
4. False negative (someone is an imposter, and identifying him as NOT an imposter)

1 and 3 are not the problem since the system identifies correctly, but 2 and 4 are problematic cases.

When the system is made less sensitive (i.e. the matching is accepted for lesser similarity), the system tends to allows access to both imposters and NOT imposters more easily. Hence count of 2 will decrease and count of 4 will increase. This is what is stated in the argument.

The above also means that when the system is made more sensitive (i.e. matching is accepted for more stringent similarity), the system tends to restrict access for both imposters and NOT imposters. Hence count of 2 will increase and count of 4 will decrease. This is option B.

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Biometric access-control systems those using fingerprints,   [#permalink] 24 Jul 2016, 15:09
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