The table shows estimates of herbaceous forage production in tons on

Question

The table shows estimates of herbaceous forage production in tons on the National Elk Refuge in Wyoming for 15 years from 1998 to 2012. Forage production measures the amount of food available to elk and bison during a growing season. Herbaceous forage includes vegetation such as grasses, forbs (nonwoody broad-leaved plants), and weeds.
 
   Year 
 Grass 
 Forb 
 Weed 
 Total Herbaceous Forage 
 
  1998 
 17,655 
 1,849 
 170 
 19,674 
 
  1999 
 13,904 
 1,924 
 0 
 15,828 
 
  2000 
 9,879 
 1,304 
 116 
 11,299 
 
  2001 
 7,641 
 1,353 
 65 
 9,059 
 
  2002 
 7,980 
 1,323 
 228 
 9,531 
 
  2003 
 5,185 
 1,007 
 218 
 6,410 
 
  2004 
 16,324 
 2,927 
 345 
 19,596 
 
  2005 
 15,881 
 2,011 
 98 
 17,990 
 
  2006 
 12,757 
 2,523 
 187 
 15,467 
 
  2007 
 10,019 
 1,310 
 45 
 11,374 
 
  2008 
 13,087 
 3,272 
 57 
 16,416 
 
  2009 
 15,100 
 2,524 
 11 
 17,635 
 
  2010 
 11,374 
 2,241 
 37 
 13,652 
 
  2011 
 15,677 
 2,226 
 4 
 17,907 
 
  2012 
 9,873 
 1,800 
 7 
 11,680 
 
   Annual average  
  12,156  
  2,126  
  106  
  14,388

For each of the following statements, select  True  if the information in the table accurately supports the statement. Otherwise, select  Not true .

Bunuel · Answer

Official Solution: Statement 1: Sort the table by Forbs production. Going through the data, we can easily notice that the year when forbs represented the largest percentage of herbaceous forage was 2008, with 3,272 tons, which was approximately 20%. All other years have a lower percentage. The 3,272 tons of forbs is approximately 50% more than the average of 2,126 for forbs. Therefore, this statement is True. Statement 2: The median value for 15 years is the 8th largest value. Sorting the table by Grass, Forb, and Weed production, we find that the medians were 12,757 tons, 1,924 tons, and 65 tons, respectively. Meanwhile, the averages for Grass, Forb, and Weed were 12,156 tons (less than the median), 2,126 tons (greater than the median), and 106 tons (greater than the median), respectively. Therefore, this statement is False. Statement 3: Two data sets are positively correlated if they both tend to be higher in the same cases. They are negatively correlated if one tends to be higher in cases where the other is lower. For positively correlated data, their lines tend to slope up or down together; the more consistently this happens, the stronger the positive correlation. Conversely, when two data sets are negatively correlated, the line for one tends to slope up while the other slopes down, and vice versa. The more consistently these opposite slopes occur, the stronger the negative correlation. Examining Grass production and Total Herbaceous Forage production over the years, we observe that in most cases, when one increases, the other also increases. This indicates that, if anything, these data are positively correlated. Therefore, this statement is False. Correct answer: Forbs production in the year when forbs represented the largest percentage of herbaceous forage was more than 30% higher than the average forbs production. "True" The median production value for each of Grass, Forb, and Weed was greater than the corresponding average production. "False" The table shows a negative correlation between Grass production and Total Herbaceous Forage production over the years. "False" GMAT-Club-Forum-i51cnqi6.png

Bismuth83 · Answer

1. Based on the information, we have to  check whether the statements are true or false .

2.  Forbs production in the year when forbs represented the largest percentage of herbaceous forage was more than 30% higher than the average forbs production.  Forbs represented the largest percentage of herbaceous forage during 2008:  \frac{3272}{16416} * 100\% = 19.93\% . The production of forbs was greater than the annual average by  \frac{3272 - 2126}{2126} * 100\% = 53.9\% , which is more than 30%.   So, this statement is true.

3.  The median production value for each of Grass, Forb, and Weed was greater than the corresponding average production.  The median for Weed is 65, while the average is 106.   So, this statement is false.

4.  The table shows a negative correlation between Grass production and Total Herbaceous Forage production over the years.  Rather, whenever one value decreases or increases, the other does the same and vice versa. This means that they're positively correlated.   So, this statement is false.

khushiagarwal_8 · Answer

Can you tell me how you can quickly check the percentage of all the categories, as required in part 1 of this question? In the Tables and Graphs question, fast calculation of such percentages of different categories is the most time-consuming and confusing for me.

Bunuel · Answer

Approximate and simplify the numbers where possible. Here's how:

3,272 and 16,416 approximate to 3.2 and 16, giving 20% (since 3.2 is 20% of 16). 
 2,927 and 19,596 approximate to 3 and 20, which is less than 20% (20% would require 4, not 3). 
 2,524 and 17,635 approximate to 2.5 and 18, which is less than 20% (20% would require 3.6, not 2.5).

Continue this way to compare the ratios efficiently without needing exact calculations.

khushiagarwal_8 · Answer

Ok. Thankyou for your help.

bumpbot · Answer

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The table shows estimates of herbaceous forage production in tons on

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Year	Grass	Forb	Weed	Total Herbaceous Forage
1998	17,655	1,849	170	19,674
1999	13,904	1,924	0	15,828
2000	9,879	1,304	116	11,299
2001	7,641	1,353	65	9,059
2002	7,980	1,323	228	9,531
2003	5,185	1,007	218	6,410
2004	16,324	2,927	345	19,596
2005	15,881	2,011	98	17,990
2006	12,757	2,523	187	15,467
2007	10,019	1,310	45	11,374
2008	13,087	3,272	57	16,416
2009	15,100	2,524	11	17,635
2010	11,374	2,241	37	13,652
2011	15,677	2,226	4	17,907
2012	9,873	1,800	7	11,680
Annual average	12,156	2,126	106	14,388

True	False
		Forbs production in the year when forbs represented the largest percentage of herbaceous forage was more than 30% higher than the average forbs production.
		The median production value for each of Grass, Forb, and Weed was greater than the corresponding average production.
		The table shows a negative correlation between Grass production and Total Herbaceous Forage production over the years.

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The table shows estimates of herbaceous forage production in tons on

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