At the end of each year, the Harcar Corporation assigns a rating to ea

Question

https://gmatclub.com/forum/download/file.php?mode=view&id=55323 At the end of each year, the Harcar Corporation assigns a rating to each member of its sales staff. The sales ratings are based on the mean (μ) and standard deviation (σ) for the individual sales totals for the year. The rating is computed by applying the following formula and then rounding the result to the nearest integer. Individual \ rating=\frac{individual \ total-μ}{σ} Sales staff are considered for promotion if their rating is 3. The graph shows the ratings for the entire sales staff for the years 2009, 2010, and 2011. 1. The graph GRAPH_1_PLACEHOLDER the claim that the sales staff had the fewest members in 2010. 2. The graph GRAPH_2_PLACEHOLDER the claim that, as a group, the staff’s total sales were highest in 2011. 1234.jpg

egmat · Accepted Answer

A cursory glance at this question may make this question appear too difficult – the definition of standard mean and deviation and the calculation of rating from these measures. But once you truly understand the dataset, you will be able to answer this question with confidence.

As you watch the solution, get answers to the following question:
 
 For question 1, did you answer through visualization without any calculations or did you compute the sum? 
 For question 2, were you able to reason out why the data presented is not sufficient to answer the question asked?

https://www.youtube.com/watch?v=sOqdGWmt77g

If you answer to both questions is YES, then you have demonstrated the skills required to answer this GI question. If any of the answers is NO, then you should work on the skill of ‘owning the dataset’.
Happy Learning.

mSKR · Answer

2010 : graph is higher than other 2 graphs in ratings ( -3,-2,-1,1,2) and at 2nd top ( 0 and 3)
It means staff members were not lowest in 2010 by summing up all staff members
>>REFUTES

2011( lowest in all ratings in graph)
We don’t know if only few staff members in 2011 with higher rating could have high revenue that could be higher than overall sum of stff members with ratings over other years
>> Nor supports neither refute
Approach2:

Case1:
Say staff sales numbers= 10,20,30,40,50,60,70$; mean= 40
Standard deviation = sqrt (30)^2 + 20^2+10^2+0 +10^2+20^2+30^2)/7= 20

Rating 3= (individual total ( 70)- 40(mean))/(20) = 1.5
Rating2: 60-40/20 = 1
Rating1= 0.5
Rating0 = 0
Rating -1= -0.5
Rating -2= -1
Rating -3= -1.5

Case2:
Above ratings could be achieved if we choose the numbers
100,200,300,400,500,600,700$; mean= 400
Standard deviation = 200
Rating 3= (individual total ( 700)- 400(mean))/(200) = 1.5

If we need to calculate for different years, without any individual sales figure we can not determine total sales

>> Nor supports neither refute

bM22 · Answer

1. The graph_____________the claim that the sales staff had the fewest members in 2010.

For sales to be lowest in 2010, there would have to be least or no promotions in 2010, which would depend on the ratings from 2009.
We can infer from the chart, that the the fewest members would have been in 2011, since the number with rating was even lower in 2010 and lowest in 2011 for a rating of 3.

So the graph refutes the claim.

Answer B.
 
2.The graph_____________the claim that, as a group, the staff’s total sales were highest in 2011.

I am choosing Nor supports neither refute, since no inference can be made, to the claim that the staff’s total sales were highest in 2011.

Answer C.

Apt0810 · Answer

1)B,since for fewest members in a particular year,it depends on the number of promotions,which ultimately depend on the sales,but if we see the graph to know the number of people who achieved 3 rating,we would find that the number of people who get 3 is continuously decreasing so fewest members would be in 2011 since in 2010 less people got 3 rating than the number who got in 2009

2)C,Since no inferences can be made just on seeing the ratings because we don't know the mean and standard deviations ,through which if put all these things in the given formula to compute the total sales in a year

Posted from my mobile device

Rohi02 · Answer

Case1- Option B: Refutes

The graph for 2011 has highest number (members) with ratings at -3,-2,-1,1,2 and second highest at 0 and 3, which no where claims that the graph had the fewest members in the year 2011. 
Therefore refutes the claim.

Case2-  Option C  : Nor supports neither refute
There hasn't been any mention of the sales figure or any correlation with the data provided. Therefore it can't be infered that the sales were highest in 2011.

Sajjad1994 · Answer

Official Explanation

RO1

The graph indicates that there were a greater number of 2010 sales members than 2011 sales members in every sales rating category. Thus, there must have been more sales members in 2010 than in 2011, refuting the claim that the sales staff had the fewest members in 2010.

The correct answer is refutes.

RO2

Each individual's sales total could be calculated from his or her rating by the formula individual total = (individual rating) + if values for and were known. These values are, however, not known. Thus, it is impossible to determine the individual sales totals and, therefore, impossible to determine the staff's total sales which may or may not have been highest in 2011.

The correct answer is neither supports nor refutes.

GMAT745owner · Answer

the graph represents a  relative  rating of salespersons within one company. if they sold more than the average sales of this year, they will receive a higher rating such as 1 or 2 or 3 and contribute to one in the height of a bar in one year. 
Q1 2010 actually has the highest salespersons by summing up the bars by each color. 
Q2 the staff’s total sales were highest in 2011. this statement can’t be proved because the graph only shows relative scores/sales. We don’t know whether the average sale of each year is the same.

Adit_ · Answer

Biggest learning is:
Converting the question asked into a understandable form forgetting the graph entirely and spending 30sec maybe 1 min just visualising goes a long way.
This question simply asks 
1) Can i determine number of sales ppl of some year (Yes, and the graph refutes)
2) Can I compare between the sales of different years (No because each year will have its own mean and SD it need not be same)

At the end of each year, the Harcar Corporation assigns a rating to ea

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At the end of each year, the Harcar Corporation assigns a rating to ea

Prep Toolkit

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

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My Rewards