The table summarizes information in several categories about the 9

Question

The table summarizes information in several categories about the 9 stores in a small grocery chain. The table also includes chain-wide averages where appropriate.

Store	Self-check express lanes	Self-check unlimited lanes	Pharmacy	Fuel	Restaurant	Average customer age
A	8	4	yes	no	no	34.5
B	8	6	no	no	no	28.4
C	6	4	yes	no	yes	32
D	8	0	yes	no	no	50.5
E	12	4	yes	yes	no	42.5
F	8	6	no	no	yes	34.6
G	8	0	no	yes	no	38.8
H	4	8	yes	no	yes	29.9
I	0	0	yes	yes	yes	56.7
averages	6.89	3.56	-	-	-	38.66

For each of the following statements, select True if the statement can be verified to be true based on the information provided. Otherwise, select False.

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ID: 100336

Also, there is a DIFFERENT QUESTION but using the same table with different question options:
https://gmatclub.com/forum/the-table-su ... 35269.html

guddo · Accepted Answer

hi there, first sort the average customer age field. You will notice the trend that as age increases, the number of self check unlimited lanes decreases. Like any set of real world data, don't expect it to be perfect. One or two outlier points can be expected. However, do look at the overall/big picture. For the most part, the number of self check unlimited lanes decreases with increasing age. Also the difference in age from 28.4 to 29.4 is small so the two dots on a scatter plot would be relatively close together without skewing the overall trend.

souvik101990 · Answer

Yes I agree with  Nicoz .

I have also seen these problems in the GMAT again and again. The GMAT does not expect you to calculate the exact correlation coefficent or standard deviation as long as the trend is loud and clear. A few values may be here or there, but if there is an overall trend that is fairly spottable, you need to be able to identify it.

I remember a similar problems around standard deviation in my own GMAT take a few weeks ago where the question asked which one would have a higher standard deviation.

Sajjad1994 · Answer

Official Explanation

The last row in the "Self-check express lanes" column indicates that the average number of self-check express lanes per store is 6.89. The only two stores with average customer ages between 34 and 36 are Store A and Store F, each of which has 8 self-check express lanes—more than the average number, 6.89. So in each store with an average customer age between 34 and 36, the number of self-check express lanes is above average.

The correct answer is True.

Sorting the table by the "Average customer age" column, we see that stores with higher average customer ages generally tend to have fewer self-check unlimited lanes. Thus, the table shows a negative correlation between average customer age and the number of self-check unlimited lanes.

The correct answer is True.

Sorting the table by the "Self-check express lanes" column, we see that all three stores with less than the average number of self-check express lanes have restaurants, whereas only one store of the six with more than the average number of self-check express lanes has a restaurant. Thus, stores with fewer self-check express lanes than average are more likely to have restaurants than are stores with more self-check express lanes than average, not less likely.

The correct answer is False.

KarishmaB · Answer

In each store whose average customer age falls between 34 and 36, the number of self-check express lanes is above average. Sort by average customer age. Stores A and F are between 34 and 36. The number of self-check express lanes at both these stores is 8, which is higher than 6.89 (the average). Select True There is a negative correlation between the number of self-check unlimited lanes and the average customer age. The table is already sorted by customer age. Note the trend. The ages lower than average age have more number of self-check unlimited lanes (6s, 8s, 4s). The ages higher than average age have fewer lanes (0s and a 4). So the trend is clear. There is negative correlation. Correlation discussed here: https://youtu.be/Zx-PysHlhGM Select True Stores in this table that have fewer self-check express lanes than the chain-wide average are less likely to have restaurants than stores that have more self-check express lanes than the chain-wide average. Sort by 'number of self-check express lanes'. I, H and C have fewer than average. All 3 have restaurants so it is 100% probability. Many stores that have more self-check express lanes than the average have no restaurant. So their probability is certainly much lower. Select False

borzovata · Answer

As for the third statement, sort the table by Self-check express lanes. Look above the average and below the average. There are three stores (I, H, C) below the average. All of them do have restaurants. On the other hand, there are six stores (A, B, D, F, G, E) above the average. Most of them do not have restaurants. It is stated that stores with fewer lanes are less likely to have restaurants than stores with more lanes. But it's quite on the contrary. So, the statement is false.

Apt0810 · Answer

1) In store A -average customer age = 34.5 ->SCEL-8(>6.89-average),Store F also has SCEL 8 ---True
2)True - Since SCUL increases and the Avg customer age decreases
3)False - I is the exception here

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RoughBook · Answer

2)True - Since SCUL increases and the Avg customer age decreases

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Can someone please explain this. There are exceptions at 6, 8 and one of the fours if we arrange it according to ACA in ascending order.

bb · Answer

I agree. There is a negative correlation trend between age and SCUL (nice acronym) but there are exceptions, so I answered "no" as well... I will have to ask for help from someone with more IR experience as to why GMAC would classify this as "True"

Nicoz · Answer

It would be a negative correlation, so that’s true. In data analysis, one or two points can have different values means they are non-correlated but overall if you plot them and draw a line of correlation it would come out as negatively correlated with the function or factor compared.

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bb · Answer

Thanks! Now that you explain it, that makes sense.

but I did not like having a few values that were not fitting in the pattern....

unraveled · Answer

For the second question, we have increasing SCUL in the order 
      H=8 
      29.9

So for SCUL from 0 to 8, either ACA decreases from 56.7 to 29.9 or 50.5 to 29.9 or 38.8 to 29.9.
Hence a negative correlation. TRUE then.

r0g3rthat · Answer

I might be wrong in this approach, but if we take average of (average age values) for same no. of SCUL, it would certainly show a negative correlation.

SUCL - Avg(Avg Age)
0 - 48.5
4 - 36.33
6 - 31.5
8 - 29.9

This shows a negative correlation.

PS: I too marked it as a "False" in GMAT Prep.

Gemmie · Answer

1. In each store whose average customer age falls between 34 and 36, the number of self-check express lanes is above average. => True

Sort by age, btw 34 and 36 is A, F 
Each has 8 Express lanes => more than avg (6.89)

2. There is a negative correlation between the number of self-check unlimited lanes and the average customer age. => True

Keept sorting by age (ascending), the number of Unlimited lanes is in general descending

3. Stores in this table that have fewer self-check express lanes than the chain-wide average are less likely to have restaurants than stores that have more self-check express lanes than the chain-wide average. => False

Sort by Express lanes
 
 Those having fewer Express lanes than Avg is are I H C ==> all 3 have restaurants 
 The remaining (have more Express lanes than Avg): most don't have  
==> Should be MORE LIKELY rather than LESS LIKELY

Prakruti_Patil · Answer

This eGMAT article helped a lot in understanding corelation traps better: https://e-gmat.com/blogs/gmat-mastery-c ... ssentials/

I fell into the trap of considering inconsistencies too important to decide the trend!

samarpan.g28 · Answer

Hi  Akkiiii , let me help you. Negative correlation means if data in one column increases, then in other column to which we are correlating will decrease. If we sort the data in the column Self-check unlimited lanes, we will see that out of the total 9 values in the Average Customer Age column, 3 times it increases only and the rest 6 times it decreases from its previous cell. Additionally, the topmost and bottommost values in the Average Customer Age column suggest that the ages are sorted in descending order. Therefore, there is a negative correlation.

I hope it helps.

Arpitamitra · Answer

Can somebody help me understand Question 3.

chetan2u · Answer

Stores in this table that have fewer self-check express lanes than the chain-wide average are   less likely   to have restaurants than stores that have more self-check express lanes than the chain-wide average.

For checking the option, sort the table by  self-check express lanes .

I, H and C are below averages, but all three have YES in the retaurant column, so almost 100% likelihood.
On the other hand all othe rabove chain-wide average have NO in all excepy one case under Restaurant column.

SO, we can say that  Stores that have fewer self-check express lanes than the chain-wide average are  more likely  to have restaurants than stores that have more self-check express lanes than the chain-wide average.

Hence, not true.

Sachdeep · Answer

I think you sorted the self check express lanes instead of self check unlimited lanes

nikitathegreat · Answer

Can someone draw a graph for the second question and show how negative correlation is depicted. To meet the values look all very scattered. It feels as if there is no correlation. I am not sure how are we saying that it is a negative correlation?
Thanks

The table summarizes information in several categories about the 9

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True	False
		In each store whose average customer age falls between 34 and 36, the number of self-check express lanes is above average.
		There is a negative correlation between the number of self-check unlimited lanes and the average customer age.
		Stores in this table that have fewer self-check express lanes than the chain-wide average are less likely to have restaurants than stores that have more self-check express lanes than the chain-wide average.

True	False	Statements
		In each store whose average customer age falls between 34 and 36, the number of self-check express lanes is above average.
		There is a negative correlation between the number of self-check unlimited lanes and the average customer age.
		Stores in this table that have fewer self-check express lanes than the chain-wide average are less likely to have restaurants than stores that have more self-check express lanes than the chain-wide average.

GMAT Graphs and Tables (G&T) Questions

The table summarizes information in several categories about the 9

Prep Toolkit

615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

745 with Only Self-Prep and GMAT Club

From 555 to 765: 210-point Improvement

Perfect 805 Score Debrief by Julia

My Rewards