Data Insights Ep. 2: Graphical Interpretation -- Fun with Unusual Graphs

Confused by unusual graphs on Graphical Interpretation questions? Unsure how to get started when a display looks unfamiliar or overwhelming? If so, you've come to the right place.
In this lesson, Tim -- a GMAT Ninja tutor -- will present some unusual-looking graphs from Graphical Interpretation questions, and discuss the 4 steps for navigating their challenges: 1) Relax 2) Start with what you know for sure 3) Identify what you don’t understand, and fill in the gaps as needed 4) If all else fails, follow a single point on the graph to figure out the bigger picture.
This is video #2 in our full-coverage series for the Data Insights section of the new GMAT Focus Edition. For updates on upcoming videos, please subscribe!
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Chapters:
00:02 Introduction
02:50 Pssg. 1
06:20 Question 1
15:49 Pssg. 2
21:25 Question 2
27:42 Pssg. 3
30:44 Question 3
38:14 Pssg. 4
41:07 Question 4
46:32 Conclusion

[@bigchonk8979]

Tim is definitely one of the best tutors here, thanks a lot gmat ninja for the whole series, super grateful!

[@GMATNinjaTutoring]

Thank you so much for the kind words! Aussie accents definitely make GMAT videos better. ;) Have fun studying!

[@sims_ran]

Is this Tim's debut on the channel? :D Can't wait!

[@TanyaKeshri-ki6me]

His teaching style is amazing. Will try and solve solve DI questions with same enthusiasm.

[@GMATNinjaTutoring]

Thank you so much for the kind words! Tim is definitely one of a kind -- we hired him partly for his lovely Aussie humor. Thank you again, and have fun studying!

[@Thatcaffeinatedgirl]

Really helpful, loved the light jokes amidst these strange graphs!

[@shagungupta199]

This was so interactive and funny! Thank you Gmat Ninja Tutoring for the best videos!

[@GMATNinjaTutoring]

Thank you so much! Tim is indeed a funny dude. We're glad that you enjoyed it, and have fun studying!

[@ashishsinha9035]

Thanks Tim and GMAT Ninja for giving us a glimpse of unusual graphs !

[@GMATNinjaTutoring]

Thank you again for watching!

[@viethungho3871]

A great video! Just one thing from me that it would be clearer to have the answer of the questions displayed also in the video :)

[@khushbuwankhede4609]

The humor made the problems breezy. Hope to see videos from Tim.

[@GMATNinjaTutoring]

Thank you! Tim's Aussie humor is indeed wonderful. :)

[@alok13070]

@@GMATNinjaTutoring does GMAT fe has negative marking?

[@dhruvjoshi4861]

Great video Tim. Can you please help me with the last question. I am not able to understand the logic behind it.

[@c6566]

defining 'the average transaction' was a bit tough as the passage mentioned 'customer transaction'. How is average tranaction = sales / size of customer transaction? 0.0;;; -> this just blew my mind. Can you please help to elaborate?

[@harshagrawal8593]

Basically Total sales of an area = (Average transaction value of that area) * (No. of transactions in that area) Hence Sales/no. of transaction( customer transaction) = average value of transaction value of transaction here is money involved in transaction while customer transaction is frequency of transactions hope this helps

[@justzzzzletgo]

These graphs were so fun to solve,honestly. Thank you so much! I have a question. I actually don't understand how white dwarf was chosen over red giants in the 2nd graph , 2nd question. A little bit more of explanation would be very helpful. Thanks a lot!.

[@GMATNinjaTutoring]

Take another look at the scale at the bottom of this graph -- it doesn't go up in even steps. Even though the red giants are taking up more space on the graph than the white dwarfs, the range of the temperatures for the red giants is smaller than the range of temperatures for the white dwarfs. The maximum temperature of the red giant stars is approximately 10,000K and the minimum temperature is approximately 3,500K (We don't need to be THAT precise with these measurements. We'll see what in a minute.) The maximum temperature of the white dwarfs is approximately 35,000K and the minimum temperature is approximately 15,000K. This means the range of temperatures for the red giants is approximately 6,500K and the range of temperature for the white dwarfs is approximately 20,000K. The reason we didn't need to be precise with the measurements of the maximum and minimum temperatures above is that the difference in the range is so big that being a little bit off with our measurements wouldn't change the final answer. I hope that helps!

[@justzzzzletgo]

@@GMATNinjaTutoring Thank you so much for this! Appreciate the help!!

[@hikatube808]

This was great - thank you! I have to say,..the last question really threw me off in how the 1 & 2 were in the middle of the line (like __1__) It threw me off cause I did not know if that was also an extra Hard factor that meant I have to choose something that would make it 818 vs 16116 Wish it would be written 1____ and 2____

[@uditdhiman850]

Hi Tim. Great video explanation. I have a doubt in Question 2 part 1. As per graph, main sequence are the ones extending from 10(-4) to 10(4) luminosity. How can we say that it represents the Sun (with L as 1). Are we saying the average is falling at middle, so that's why we are taking Sun as the "main sequence" star?

[@GMATNinjaTutoring]

The text describing the graph tells us that the y-axis represents the "luminosity (rate of energy emission) relative to the Sun (LSun)." Since this luminosity rate is RELATIVE TO THE SUN, the sun will have a luminosity rate of 1. If you could draw a horizontal line across the graph that went through the y-axis at 1, the only group of stars the line would cross is the main sequence stars. This means the sun must be a main sequence star, and that's the answer to this question. I hope that helps!

[@uditdhiman850]

@@GMATNinjaTutoring could you please mention luminosity range of "main sequence" stars.

[@GMATNinjaTutoring]

@@uditdhiman850 the luminosity range of the main sequence stars goes from roughly 10^(-4) to 10^4. However, you could change either of these numbers (or both of them) and it wouldn't change the answer to this question as the important thing is that the sun has a relative luminosity of 1, and the only kind of stars that could have a luminosity of 1 in the graph are the main sequence stars.

[@uditdhiman850]

@@GMATNinjaTutoring thank you

[@mayanksureka708]

BEST TUTOR HERE

[@ezumagrace4963]

Charlie's goofiness has been matched 🤣 Good to have you here, Tim

[@GMATNinjaTutoring]

Yes, but his accent has been beaten soundly. And his nose is still unmatched. 😆

[@anadyanix]

Hey great set of videos. Very helpful. Can you please elaborate the explanation for question 2 part one with sun

[@GMATNinjaTutoring]

The text describing the graph tells us that the y-axis represents the "luminosity (rate of energy emission) relative to the Sun (LSun)." Since this luminosity rate is RELATIVE TO THE SUN, the sun will have a luminosity rate of 1. If you could draw a horizontal line across the graph that went through the y-axis at 1, the only group of stars the line would cross is the main sequence stars. This means the sun must be a main sequence star, and that's the answer to this question. I hope that helps!

[@vidditharia2537]

Could you give a brief explanation of the white dwarf and blue giants graph Q2? I didn’t understand how the range of white dwarfs is larger than blue giants

[@GMATNinjaTutoring]

The temperature of the stars is given on the x-axis, so we need to look at the horizontal spread of each type of star while being careful to notice that the scale on the x-axis is not linear. Thankfully, the blue giant and white dwarf stars are in the same horizontal region of the graph, so we don't have to worry too much about the changing scale on the x-axis. This means we can focus on the horizontal spread of these two groups of stars: the greater the spread, the greater the temperature range. If we look at the horizontal spread of the white dwarf and blue giant stars, the spread of the blue giant stars is totally contained within the spread of the white dwarf stars. This means the white dwarf stars have a greater range of temperatures than the blue giant stars. I hope that helps!

[@hardikjagga7190]

whats the level for these types of questions

[@Catnidhi]

Tim!!! Big fan 🤯 Also, the range of blue giants extends upto 40K and not stop at 30K. That range qn is still confusing!

[@DelusionalRaptor]

It's a bit misleading there but the blue giants are just the two you see near ~20k kelvin and 10^6 luminosity. the smaller blue dots, including the one at 40k, is considered part of the main sequence.

[@kanikamalhotra818]

For the last question I feel the blanks make the question confusing to answer although I was able to label everything correctly

[@mariaben5383]

This was so much fun! Thanks Tim :)

[@GMATNinjaTutoring]

Best comment ever! I'm glad that you actually thought it was fun. We try to make the GMAT not-so-torturous, but it doesn't always work. :) Enjoy your studies, and thank you again for the message!

[@pennypeng5785]

I am a bit confused regarding Q2 of Q2. So the tiny dark blue and light blue bubbles are not blue giants, they are main sequences? The blue giants are the two bigger bubbles?

[@vardanrathi7777]

Yes

[@pennypeng5785]

@@vardanrathi7777 Ok thanks!

[@Basiliokarani]

the first question you did answer the first part!! could you please drop us the answer? it would really help us

[@GMATNinjaTutoring]

Tim gave the answer to the first question at about 10:20. The region with the most Techtyx customer transactions ranks *FOURTH* in the number of product types marketed there. I hope that helps!

[@Basiliokarani]

@@GMATNinjaTutoring I see now. Thanks for the response. Tell Charles I'm a big fan!

[@RitikKumar-qe3lw]

In q2 there are two main sequence points in graph one is with lower luminosity, why did we not consider that ?

[@GMATNinjaTutoring]

The main sequences stars are all the ones in the large diagonal strip running from the top left of the graph to the bottom right. There are many more than two of them, and they cover almost the whole range of temperate and luminosity. Are you sure you meant the main sequence stars in your question? Perhaps you meant the blue giants?

[@su7sh]

45:50 does like D -> A, A -> D also work? Mathematically it does hence the question. tyia

[@GMATNinjaTutoring]

As Tim demonstrated in the video, if the node between B and C has a value of 1, then A = 8, B = 2, C = 2, D = 16, and E = 2. This means that the only possible answer to the two blanks is D for the first blank and A for the second blank as D is twice as large as A. A -> D cannot work because A is *not* "exactly double the value of" D. I hope that helps!

[@su7sh]

@@GMATNinjaTutoringYes. Thank you!

[@vaibhavbhatia4641]

Please mark answers to the question at the end. Thanks

[@tejasrsingh]

1:00 definetely me

[@matteobuscaglia3217]

In Q2, why do we say that the blue giants are incapsulated in white dwarfs? to me it seem the exact opposite

[@GMATNinjaTutoring]

If you measure the temperature range of each set of stars by checking the horizontal length of the group of blue giant stars and that of the group of white dwarf stars, then the length of the blue giant stars is entirely contained within the length of the white dwarf stars. In other words, the blue giants' temperature range goes from approximately 18,000K to 30,000K while the white dwarfs' temperature range goes from approximately 15,000K to 37,500K. From this, we can say the temperature range of the blue giants is encapsulated within the temperature range of the white dwarfs. I hope that helps!

[@matteobuscaglia3217]

@@GMATNinjaTutoring yeah sure, i made a stupid mistake. i was considering the main sequence blue section as the blue giants

[@thehappygoluckygirll.9]

What is the level of these questions?

[@UtkarshVardhan-j2t]

Hey Tim, even I would like to know what score bracket these questions fall into

[@hrishikeshbarokar7602]

LMFAO you're too funny dude

[@GMATNinjaTutoring]

Aussie humor is the best. :)

[@Analyst2019pro]

What? For the bubble question it should rank 1st not 4th, given it is larger.

[@GMATNinjaTutoring]

The size of the bubble and the number within the bubble tell us the proportion of Thechtyx customer transactions that took place in that region. Region C has the greatest number in the bubble, so this is the region that this question is concerned with. We're then asked where that region ranks "in the number of product types marketed there." The number of product types marketed in a region is given by the vertical axis. Regions D, E, and F are all higher in the y-direction than region C, so region C ranks 4th in the number of product types marketed in a region. I hope that helps!

[@meghasehgal1429]

@@GMATNinjaTutoring I marked my answer as third. I counted it as A->B->C, in ascending order. But seems like we have an unspoken rule here to calculate it in descending order (largest to smallest). Please confirm, thanks.

[@dradoode]

@@meghasehgal1429this is how I answered it too. Would love to hear why they went in descending order

[@bombaybarbell]

@@dradoode I think because ranking works from best to worst. Whenever we see ranks, it starts from first to last.

[@Danaschiller]

I'm so sorry, but it's hard to focus during this video without you writing on the board, and not displaying the Right answer.

[@thisisakr]

So hot xD