Cheever College offers several online courses via remote computer conn

Here we have another inference question, so we don't have a conclusion with a well-structured line of reasoning. As always, make sure that you clearly understand the given information and pay attention to the details:

• Cheever College offers traditional classroom-based courses (CBCs) AND several online courses (OCs) via remote computer connection.
• According to a study, the average student grade for OCs was the same as the average student grade for CBCs.
• When calculating average grade for that study, course withdrawals were weighted as equivalent to a course failure.
• The rate of withdrawal was much lower for CBC students than for OC students.

OC students were more likely to withdraw. In the eyes of the study, those students who withdrew failed the course. So before factoring in the students who did NOT withdraw, we are starting with a higher proportion of failure among the OC students. For example, if there were twice as many withdrawals from OCs as there were from CBCs, then we'd be starting with a failure rate that is twice as high among OC students as it is for CBC students (again, BEFORE factoring in the students who did not withdraw).

Now let's factor in the students who did NOT withdraw. Let's say that the average grade among OC students who did not withdraw was the SAME as the average grade among CBC students who did not withdraw. As stated above, there were more OC withdrawals. So if the non-withdrawal averages are equal and there are more OC withdrawals, then the overall average of OC students would have to be lower than the overall average of CBC students.

But we are told that this is not the case and that the overall averages are the same for both groups. Remember, when we are just looking at the withdrawals, we are starting with a higher failure proportion among OC students. In order for the average of the OC students to "catch-up" to the average of the CBC students, the average of the OC students who did NOT withdraw would have to be HIGHER than the average of the CBC students who did not withdraw. Otherwise, the CBC students would have a higher overall average.


As described in the preceding analysis, choice (A) has to be true. Keep this one.


The study is concerned with AVERAGE grades, so we cannot determine anything about the actual number of students per course. Eliminate (B).


The study compares average student grade for OCs to average student grade for CBCs. This study could be conducted even if some students took both types of courses. The study would simply include the student's OC grades in the OC average and include the student's CBC grades in the CBC average. So we might have students who took both types and we might not. (C) cannot be determined.


As with choice (B), the findings involve AVERAGE grades. It is certainly possible that a large portion of the students with the BEST grades took CBCs. As long as the AVERAGE of OC students who did not withdraw was higher than the AVERAGE of the CBC students who did not withdraw, it doesn't matter which group has the students with the BEST grades. For example, it is possible that the 10 best students all took CBCs, the rest of the CBC students did poorly, and most of the OC students did fairly well.

Choice (D) might be true, but we don't know for sure. And we certainly cannot determine that a significant majority of the students with the best grades took OCs rather than CBCs. Eliminate (D).


The information in the passage does not offer any evidence to EXPLAIN the data. All we can determine is that the average of the OC students who did NOT withdraw has to be higher than the average of the CBC students who did not withdraw. A number of factors could explain this result (better teachers, better courses, etc). Choice (E) is a possible explanation, but we cannot determine whether it is true based on the information in the passage. Eliminate (E).

Choice (A) is the only statement that HAS to be true.
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Hi Ankur,

You are correct in rejecting options C, D, and E as OFS.

However, the reasons for selecting option B and rejecting option A are correct.

First, let's talk about option B:

(B) The number of students enrolled per course at the start of the school term is much higher, on average, for the online courses than for the classroom-based courses.

Nowhere does the passage talk about number of students. The passage only talks about withdrawal rate, which refers to proportion of students who withdraw from the course. We do not know anything about the number of students in either traditional or online courses. So, option B is incorrect.

Coming to option A:

(A) Among students who did not withdraw, students enrolled in online courses got higher grades, on average, than students enrolled in classroom-based courses.

You are correct that the passage only talks about students who withdrew and not about students who did not withdrew. But what is the relation between students who withdrew and students who did not withdrew?

The relation is:

Students who did not withdrew + Students who withdrew = Total number of students enrolled

Now, we are given average grade for all the enrolled students and we also know average grade of Students who withdrew - the grade is "0" or "failed". From this, don't you think we can make some judgement about the average of students who did not withdrew.

We can!

If average grade for "all enrolled students" was same for traditional and online courses
And "Number of students who withdrew i.e. who got "Fail" grade" were higher for online courses than traditional courses
Then, in such a case, the average grade of students who did not withdrew must be higher for online courses than traditional courses.

Do you get it?

If you look back now, you can see that Students who did not withdrew and Students who withdrew constitute all the students. Right?

In such cases, where two sets constitute everything or the universe, then in a lot of cases, on the basis of information of one set, we can make inferences about the other set.

Does it help?

Thanks,
Chiranjeev
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Cheever College offers several online courses via remote computer connection, in addition to traditional classroom-based
courses. A study of student performance at Cheever found that, overall, the average student grade for online courses
matched that for classroom-based courses. In this calculation of the average grade, course withdrawals were weighted as
equivalent to a course failure, and the rate of withdrawal was much lower for students enrolled in classroom-based courses
than for students enrolled in online courses. If the statements above are true, which of the following must also be true of
Cheever College?
(A) Among students who did not withdraw, students enrolled in online courses got higher grades, on average, than students
enrolled in classroom-based courses.
(B) The number of students enrolled per course at the start of the school term is much higher, on average, for the online courses
than for the classroom-based courses.
(C) There are no students who take both an online and a classroom-based course in the same school term.
(D) Among Cheever College students with the best grades, a significant majority take online, rather than classroom- based,
courses.
(E) Courses offered online tend to deal with subject matter that is less challenging than that of classroom-based courses.

I am facing difficulty in solving this problem.

Using Inference technique as mentioned, i was able to eliminate

Option C - OFS
Option D - OFS (best grade is not talked in the passage)
Option E - OFS (less complex subject not discussed in argument)

Option A - iSAWT (I felt student who didnt withdraw got higher score is not right answer choice as the argument is only about the enrolled/withdrawl student count)

Hence, I marked option B as right choice.

Please help me in understanding what i am missing in making logical structure of this argument and in doing pre-thinking.

Thanks,
Ankur

Cheever College offers several online courses via remote computer connection, in addition to traditional classroom-based courses. A study of student performance at Cheever found that, overall, the average student grade for online courses matched that for classroom-based courses. In this calculation of the average grade, course withdrawals were weighted as equivalent to a course failure, and the rate of withdrawal was much lower for students enrolled in classroom-based courses than for students enrolled in online courses.

If the statements above are true, which of the following must also be true of Cheever College?

(A) Among students who did not withdraw, students enrolled in online courses got higher grades, on average, than students enrolled in classroom-based courses.
(B) The number of students enrolled per course at the start of the school term is much higher, on average, for the online courses than for the classroom-based courses.
(C) There are no students who take both an online and a classroom-based course in the same school term.
(D) Among Cheever College students with the best grades, a significant majority take online, rather than classroom-based, courses.
(E) Courses offered online tend to deal with subject matter that is less challenging than that of classroom-based courses.



the average student grade for online courses = the average student grade for classroom-based courses
withdrawal= failure
withdrawal for online courses > withdrawal for classroom-based courses

so it can be deduced A : to have the same average with students in classroom-based courses, students in online courses should get higher grades on average to compensate the higher withdrawal.

D is not correct bcz in the argument we don't care about the best grades, higher grades is enough to justify the equation. consider the following scenario:

in classroom based courses:
total #enrolled: 30
#withdrawal: 1 (consider withdrawal score 0)
#best score 100/100: 3
if we consider passing score 50, and if we consider the worst case: # of who just passed : 26
ave= 3*100+ 26*50= 1600/30=53.3

in online courses:
total #enrolled: 30
#withdrawal: 5
#best score 100/100: 1
and consider the best case for this group: the remaining got 99/100

ave= (100+ 24*99)/30=82.53

so, in this case the average must be higher in classroom-based courses.
and we can see what is matter here is the average higher grades not the best grades.

Cheever College offers several online courses via remote computer connection, in addition to traditional classroom-based courses. A study of student performance at Cheever found that, overall, the average student grade for online courses matched that for classroom-based courses. In this calculation of the average grade, course withdrawals were weighted as equivalent to a course failure, and the rate of withdrawal was much lower for students enrolled in classroom-based courses than for students enrolled in online courses.

If the statements above are true, which of the following must also be true of Cheever College?

(A) Among students who did not withdraw, students enrolled in online courses got higher grades, on average, than students enrolled in classroom-based courses. -Correct
(B) The number of students enrolled per course at the start of the school term is much higher, on average, for the online courses than for the classroom-based courses. -We can't say anything about the number of students
(C) There are no students who take both an online and a classroom-based course in the same school term. -Can't say
(D) Among Cheever College students with the best grades, a significant majority take online, rather than classroom-based, courses. -Can't say anything about the "best" students. We just know about the "average".
(E) Courses offered online tend to deal with subject matter that is less challenging than that of classroom-based courses. -Challenging? out of scope

IMO - A

Option A - Correct answer; If classroom guys got less F than online course enrolled guys but still have the similar average grade, the guys who completed online course must have had better grades than classroom enrolled guys.
B - Not necessary with given stem info.
C - Irrelevant, no information provided
D - Information is provided about the average grade, not the best grades. Also, no other information available about numbers of classroom students and remote course enrolled students.
E - As per stem, we are talking about each course average grade comparison so out of scope.

(A) Among students who did not withdraw, students enrolled in online courses got higher grades, on average, than students enrolled in classroom-based courses.Logical consequence of the passage. Apply statistics from quant. makes sense

(B) The number of students enrolled per course at the start of the school term is much higher, on average, for the online courses than for the classroom-based courses.New information. The passage doesn't provide the number of students enrolled at the start of the school term

(C) There are no students who take both an online and a classroom-based course in the same school term.New information

(D) Among Cheever College students with the best grades, a significant majority take online, rather than classroom-based, courses.This is a could be true option. Like a not sufficient DS statement, you will get both yes and no answer for this

(E) Courses offered online tend to deal with subject matter that is less challenging than that of classroom-based courses.New information
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The average student grade for online courses = (sum of grades of students enrolled in online courses)/ (total number of students enrolled in online courses)

And

The average student grade for classroom courses = (the sum of grades of students enrolled in classroom courses)/ ( total number of students enrolled in classroom courses)

These averages are equal right?

So even if the number of withdrawals in online courses is twice of the number of withdrawals in the classroom courses,
how can we conclude — *Among students who did not withdraw, students enrolled in online courses got higher grades, on average, than students enrolled in classroom-based courses* ??

We don’t know whether the number of people who enrolled in online courses is same as the number of people who enrolled in classroom courses

??

egmat GMATNinja

Posted from my mobile device

We don't need to know the number of people enrolled in either type of course in order to compare the averages for each type of course or the proportions of students enrolled in each type of course. In fact, any answer choice which depends on knowing any absolute numbers of students cannot be correct, for the reason you're pointing out: those numbers never appear in the passage.

Please check out our full explanation if you haven't had the chance yet, and feel free to follow up with specifics if that explanation doesn't resolve your doubt.
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GMATNinja
nightblade354
eakabuah
mira93
GMATNinjaTwo



How can you be sure that withdrawals or failure bring down a class average ? Its quite possible (l was not sure about this bit when doing the problem) - that only students who are part of the class room can bring up or bring down the average.

Where does it imply that failures = withdrawals bring down an average ?

I agree that if withdrawals / failure affect the class average, the answer is A

If withdrawals and failures weren't counted for calculation of the average grade we'd probably see something like they were "excluded" or "ignored" or "removed."

But the argument says that in the "calculation of the average grade, course withdrawals were weighted as equivalent to a course failure." That sounds like withdrawals and failures are part of the calculation of average grades. It even says that withdrawals and failures received a weight in this calculation. If they were excluded they wouldn't be receiving a weight in the calculation.

I hope that helps!
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Why are we only taking about withdrawal (W) & non Withdrawal (NW)
Why are we also no taking into consideration pure failure (PF) based cases also, i.e Non Withdrawal, however they failed the course

What if these pure failure based cases are higher in Classroom based courses (CBC), doesn't this make option A incorrect ??

The passage and (A) both make the distinction between students who withdrawal and those who do not withdrawal. Although it doesn’t explicitly mention students that simply fail the course (“pure failures”), those students are counted among those who do not withdrawal.

It’s entirely possible that both the rate of “pure failures” is higher in classroom-based courses (CBCs), and the average grade in CBCs is lower than that in online courses. In fact, if the failure rate is higher in CBCs, then that would (at least partially) explain why the average grade is lower in CBCs. That’s because failing a course would presumably weigh down the average grade. Therefore, a higher rate of failure in CBCs is entirely consistent with (A), and (A) is correct.

I hope that helps!
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SIR I HAVE A DOUBT REGARDING THIS QUESTION.
LET SUPPOSE TOTAL STUDENTS IN UNIVERSITY ARE 200
ONLINE : 150 STUDENTS
CLASSROOM : 50 STUDENTS
THE RATE OF WITHDRAWAL FOR ONLINE WAS 70% AND THE RATE OF WITHDRAWAL FOR CLASSROOM WAS 10% THEN THE FIGURE COMES AS
ONLINE : 150-70%=45
CLASSROOM : 50-10%=45
WHICH IS SAME NUMBER OF STUDENTS
THEN THE AVERAGE GRADES CAN BE SAME AND THE AVERAGE SCORE AMONG CLASSROOM STUDENTS AND ONLINE STUDENTS CAN BE MAINTAINED EVEN WITHOUT SCORING HIGHER GRADES AMONG THE ONLINE STUDENTS.

The problem is that students who've withdrawn are NOT omitted from the calculation! ("In this calculation of the average grade, course withdrawals were weighted as equivalent to a course failure...")

Using your numbers, 105 online students withdrew from their courses. That means the group of 150 already has 105 course failures, regardless of what the remaining 45 students did.

So, let's say that a course failure is equivalent to a grade of 0 on a 4-point scale. For simplicity, let's also say that each of the 90 remaining students (45 online and 45 classroom) had a grade of 3. Now let's think about the average for each group:

• For the online students, we have 105 0's and 45 3's. All of those 0's are going to pull the average closer to 0 than to 3.
• For the classroom students, we only have 5 0's to go along with those 45 3's. That means that the average is going to be very close to 3.

In order for the averages to balance out (INCLUDING the students who withdrew and who were thus marked as failing), (A) must be true.

I hope that helps!
_________________

The passage states that the average student grade for online courses at Cheever College matches that for classroom-based courses when course withdrawals are weighted as equivalent to course failures. The withdrawal rate is lower for classroom-based courses. We need to determine which statement must also be true based on this information.

Option (A) suggests that among students who did not withdraw, students enrolled in online courses achieved higher average grades than those enrolled in classroom-based courses. This statement aligns with the information provided in the passage, where the average student grade for online courses matches that for classroom-based courses when considering withdrawals as failures.

Option (B) states that the number of students enrolled per course at the start of the school term is higher, on average, for online courses compared to classroom-based courses. This information is not supported by the passage and does not necessarily have to be true based on the given information.

Option (C) claims that there are no students who take both an online and a classroom-based course in the same school term. The passage does not provide any information about whether or not students can take both types of courses, so this statement cannot be determined based on the given information.

Option (D) suggests that a significant majority of Cheever College students with the best grades take online courses rather than classroom-based courses. The passage does not provide any information regarding the choices of students with the best grades, so this statement cannot be determined based on the given information.

Option (E) implies that online courses offered at Cheever College tend to cover less challenging subject matter compared to classroom-based courses. The passage does not provide any information about the relative difficulty or subject matter of the two course formats, so this statement cannot be determined based on the given information.

In conclusion, option (A) must be true based on the information provided, as it aligns with the passage's statement that, overall, the average student grade for online courses matches that for classroom-based courses when withdrawals are considered as failures.