Points Earned vs. Hours studied

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Points Earned vs. Hours studied

by gmattesttaker2 » Sat May 24, 2014 11:15 pm
Hello,

Can you please assist with this? I was able to solve Question 1 now. Not clear though on how to solve Question 2. Thanks for your help - Sri
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by [email protected] » Sun May 25, 2014 5:24 pm
Hi Sri,

The second question on this page asks for the MEDIAN of the number of hours studied. The word "median" is a statistical term that means "the middle number of the group", so we have to make sure the numbers are in order from least to greatest and then find the one in the middle. Here, we're told that there are 33 students, so the median will be the 17th number.

Each of the colored "dots" in the table represents a student, so we just have to count until we hit the 17th one (either from left to right or from right to left).

When counting from left to right, here's what I see:
5 students studied 1 hour
9 students studied 2 hours
8 students studied 3 hours

The 17th student will fall into the "3 hours" group.

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Rich
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by gmattesttaker2 » Tue Jun 03, 2014 11:39 am
[email protected] wrote:Hi Sri,

The second question on this page asks for the MEDIAN of the number of hours studied. The word "median" is a statistical term that means "the middle number of the group", so we have to make sure the numbers are in order from least to greatest and then find the one in the middle. Here, we're told that there are 33 students, so the median will be the 17th number.

Each of the colored "dots" in the table represents a student, so we just have to count until we hit the 17th one (either from left to right or from right to left).

When counting from left to right, here's what I see:
5 students studied 1 hour
9 students studied 2 hours
8 students studied 3 hours

The 17th student will fall into the "3 hours" group.

GMAT assassins aren't born, they're made,
Rich
Hello Rich,

Thanks a lot for explaining Question 1. For Question 2 I tried to solve as follows:

Average number of hours studied by students in Section A = 23/11 = 2.09
Average number of hours studied by students in Section B = 21/11 = 1.9
Average number of hours studied by students in Section C = 6/11 = 0.5

Is this approach correct?

Thanks,
Sri

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by [email protected] » Tue Jun 03, 2014 12:11 pm
Hi Sri,

My apologies for not answering both questions in the initial post.

For the second question, you can absolutely calculate the average of the three groups, but you can also "eyeball" the table to tell which group has the smallest average study time. It's important to note that each group consists of 11 students each.

Notice how most of the points are clustered around 2 hours and 3 hours.... Groups A (the white circles) and B (the blue squares) have many terms each that are greater than 3, which would push their averages "up"; Group C (the black circles) has only 1 term above 3 (just one 4) and 2 terms at the lowest level (1 hour), which means that this must be the group with the lowest average study time.

While certain chart/graph/table questions in the IR section will require a calculation, many will not. Keep an eye out for questions that require a specific numerical answer vs. those the require a non-numeric answer. The ones that don't require a numeric answer are ones that you can likely answer by spotting a pattern.

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Rich
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by gmattesttaker2 » Wed Jun 04, 2014 9:06 pm
[email protected] wrote:Hi Sri,

My apologies for not answering both questions in the initial post.

For the second question, you can absolutely calculate the average of the three groups, but you can also "eyeball" the table to tell which group has the smallest average study time. It's important to note that each group consists of 11 students each.

Notice how most of the points are clustered around 2 hours and 3 hours.... Groups A (the white circles) and B (the blue squares) have many terms each that are greater than 3, which would push their averages "up"; Group C (the black circles) has only 1 term above 3 (just one 4) and 2 terms at the lowest level (1 hour), which means that this must be the group with the lowest average study time.

While certain chart/graph/table questions in the IR section will require a calculation, many will not. Keep an eye out for questions that require a specific numerical answer vs. those the require a non-numeric answer. The ones that don't require a numeric answer are ones that you can likely answer by spotting a pattern.

GMAT assassins aren't born, they're made,
Rich
Hello Rich,

Thanks a lot for the explanation.

Best Regards,
Sri