2385: Final Exam - Revision history

82.132.185.192: /* Explanation */ Simpler templated link format. (Aesthetically identical, but more compact/standardised markup.)

2026-05-08T14:25:49Z

‎Explanation: Simpler templated link format. (Aesthetically identical, but more compact/standardised markup.)

152.7.255.205 at 01:25, 8 May 2026

2026-05-08T01:25:33Z

1234231587678 at 03:05, 17 December 2025

2025-12-17T03:05:39Z

172.70.85.169: /* Explanation */ Individuals/sub-groups have other options, as mentioned (e.g. throwing others under (over?) the bus).

2023-05-14T08:41:52Z

‎Explanation: Individuals/sub-groups have other options, as mentioned (e.g. throwing others under (over?) the bus).

172.71.158.37: /* Explanation */

2023-05-14T05:31:31Z

‎Explanation

Theusaf: Reverted edits by Donald Trump (talk) to last revision by CRLF

2022-05-26T19:59:10Z

Reverted edits by Donald Trump (talk) to last revision by CRLF

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Donald Trump: Reverted edit by anti-crap user

2022-05-26T19:04:00Z

Reverted edit by anti-crap user

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CRLF: Reverted vandalism with User:CRLF/OneClickUndo.js

2022-05-26T18:00:45Z

Reverted vandalism with User:CRLF/OneClickUndo.js

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Donald Trump: Reverted edit by anti-crap user

2022-05-26T17:07:58Z

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Theusaf: Reverted edits by 👖🔥 (talk) to last revision by Jacky720

2022-05-11T18:44:13Z

Reverted edits by 👖🔥 (talk) to last revision by Jacky720

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@@ Line 24: / Line 24: @@
 Note: The above also assumes the system accepts a maximum of 100%.  If (as is likely) the system allows for extra credit you could reach a Nash equilibrium by setting the non-game theory students to an arbitrary, but very high, number (say 2000%) C and then the game theory students to (C*g)/(.25+g) where g is the percentage of students not in game theory.
-Note: The solution becomes trivial if the game-theory grade is stored on the same server but submitted after the cybersecurity grade. Students would simply give themselves full marks on cybersecurity, then edit the game-theory grade after cybersecurity has been submitted, demonstrating a classical [[wikipedia:Time-of-check to time-of-use|time-of-check time-of-use]] vulnerability.
+Note: The solution becomes trivial if the game-theory grade is stored on the same server but submitted after the cybersecurity grade. Students would simply give themselves full marks on cybersecurity, then edit the game-theory grade after cybersecurity has been submitted, demonstrating a classical {{w|time-of-check to time-of-use}} vulnerability.
 ==Transcript==

@@ Line 24: / Line 24: @@
 Note: The above also assumes the system accepts a maximum of 100%.  If (as is likely) the system allows for extra credit you could reach a Nash equilibrium by setting the non-game theory students to an arbitrary, but very high, number (say 2000%) C and then the game theory students to (C*g)/(.25+g) where g is the percentage of students not in game theory.
-Note: The solution becomes trivial if the game-theory grade is stored on the same server but submitted after the cybersecurity grade. Students would simply give themselves full marks on cybersecurity, then edit the game-theory grade after cybersecurity has been submitted.
+Note: The solution becomes trivial if the game-theory grade is stored on the same server but submitted after the cybersecurity grade. Students would simply give themselves full marks on cybersecurity, then edit the game-theory grade after cybersecurity has been submitted, demonstrating a classical [[wikipedia:Time-of-check to time-of-use|time-of-check time-of-use]] vulnerability.
 ==Transcript==

@@ Line 8: / Line 8: @@
 ==Explanation==
-In this comic, Ponytail appears to be administering a group sitting for cybersecurity exam. However, at the beginning of the exam, she informs her students that they have all failed, despite not having taken a test yet. She then informs them that their grades are stored on the department server and will be submitted the next day. The implication here is that the true test, rather than being a traditional exam, is actually whether the students can hack into the server and change their grades. This may be a jab at education security which is known to be vulnerable to assault ([[327: Exploits of a Mom|not the first time]] xkcd has made such a joke). In real life, students have attempted to change their grades in this manner, with occasional success.
+In this comic, Ponytail appears to be administering a group sitting for cybersecurity exam. However, at the beginning of the exam, she informs her students that they have all failed, despite not having taken a test yet. She then informs them that their grades are stored on the department server and will be submitted the next day. The implication here is that the true test, rather than being a traditional exam, is actually whether the students can hack into the server and change their grades. This may be a jab at education security which is known to be vulnerable to assault, which is not the first time xkcd has made such a [[327: Exploits of a Mom|joke]]. In real life, students have attempted to change their grades in this manner, with occasional success.
 The title text adds a twist to this. In order for a student to get a good grade in the {{w|game theory}} class, they need to get a below-average grade on this final exam. This incentivizes the students to also change the grades of other students when they change their grade. However, this is more complicated than it seems, and depends on various factors, such as the fraction of students who take game theory in addition to cybersecurity. If, for example, half of the students also take game theory, then for all of them to get 80% of the average score, even assuming that all their non-game-theory classmates get maximum possible score, they would have to target for 2/3 (or about 67%) of the maximum possible score, to get 80% of the final average. While that would make their game theory grade perfect, it might noticeably worsen their cybersecurity grade. This gets progressively worse with the increasing fraction of students who take game theory along with cybersecurity.

@@ Line 12: / Line 12: @@
 The title text adds a twist to this. In order for a student to get a good grade in the {{w|game theory}} class, they need to get a below-average grade on this final exam. This incentivizes the students to also change the grades of other students when they change their grade. However, this is more complicated than it seems, and depends on various factors, such as the fraction of students who take game theory in addition to cybersecurity. If, for example, half of the students also take game theory, then for all of them to get 80% of the average score, even assuming that all their non-game-theory classmates get maximum possible score, they would have to target for 2/3 (or about 67%) of the maximum possible score, to get 80% of the final average. While that would make their game theory grade perfect, it might noticeably worsen their cybersecurity grade. This gets progressively worse with the increasing fraction of students who take game theory along with cybersecurity.
-In the extreme case of all cybersecurity students also taking game theory class, this degenerates into another common game theory problem: {{w|Guess 2/3 of the average}} of everybody's guesses. The only winning strategy is, of course, for everyone to guess 0, which means that 2/3 of the average will be 0. This assumes {{w|perfect rationality}} of all players with respect to the game theory problem. The catch is that here we have the same number as a grade for the cybersecurity exam and for the game theory guess. We'd like one to be as high as possible, and the other to be zero or close to zero, which are obviously conflicting goals.
+In the extreme case of all cybersecurity students also taking game theory class, this degenerates into another common game theory problem: {{w|Guess 2/3 of the average}} of everybody's guesses. The only group-wide winning strategy is, of course, for everyone to guess 0, which means that 2/3 of the average will be 0. This assumes {{w|perfect rationality}} of all players with respect to the game theory problem. The catch is that here we have the same number as a grade for the cybersecurity exam and for the game theory guess. We'd like one to be as high as possible, and the other to be zero or close to zero, which are obviously conflicting goals.
 To improve their overall results, students could resort to various compromises and strategies, such as increasing other students' scores against their will, or making alliances with students who might not mind taking a hit to their game theory grade (perhaps in exchange for other incentives) - these are all topics that the game theory class would have been dealing with. Specifically, this test seems to refer to the {{w|prisoner's dilemma}} and {{w|tragedy of the commons}}; if one student changes their grade to 80% of the average, they will receive high marks, but if more and more students attempt this, the gain for each one drops and tends towards zero.

@@ Line 8: / Line 8: @@
 ==Explanation==
-In this comic, Ponytail appears to be administering a group sitting for cybersecurity exam. However, at the beginning of the exam, she informs her students that they have all failed, despite not having taken a test yet. She then informs them that their grades are stored on the department server and will be submitted the next day. The implication here is that the true test, rather than being a traditional exam, is actually whether the students can hack into the server and change their grades. This may be a jab at education security which is known to be vulnerable to assault ([[327: Exploits of a Mom|not the first time]] XKCD has made such a joke). In real life, students have attempted to change their grades in this manner, with occasional success.
+In this comic, Ponytail appears to be administering a group sitting for cybersecurity exam. However, at the beginning of the exam, she informs her students that they have all failed, despite not having taken a test yet. She then informs them that their grades are stored on the department server and will be submitted the next day. The implication here is that the true test, rather than being a traditional exam, is actually whether the students can hack into the server and change their grades. This may be a jab at education security which is known to be vulnerable to assault ([[327: Exploits of a Mom|not the first time]] xkcd has made such a joke). In real life, students have attempted to change their grades in this manner, with occasional success.
 The title text adds a twist to this. In order for a student to get a good grade in the {{w|game theory}} class, they need to get a below-average grade on this final exam. This incentivizes the students to also change the grades of other students when they change their grade. However, this is more complicated than it seems, and depends on various factors, such as the fraction of students who take game theory in addition to cybersecurity. If, for example, half of the students also take game theory, then for all of them to get 80% of the average score, even assuming that all their non-game-theory classmates get maximum possible score, they would have to target for 2/3 (or about 67%) of the maximum possible score, to get 80% of the final average. While that would make their game theory grade perfect, it might noticeably worsen their cybersecurity grade. This gets progressively worse with the increasing fraction of students who take game theory along with cybersecurity.