Consumer Price Index (CPI) measures the average prices of

[email protected] wrote:Hi Sri,

The description at the top of the table reads "Seasonally adjusted changes from the PRECEDING MONTH", which means that the number in the box is the percent increase/decrease in price of an item relative to the prior month.

For question 2, the CPI-U for electricity in July was 0.5; this means that the price of electricity was .5% HIGHER in July than in June. The CPI-U for electricity in August was 0.2; this means that the price of electricity was .2% HIGHER in August than in July. This statement asks if the increase from July to August was .5% higher. This means that the answer to this question is NO.

For question 3, we need to look at the CPI-U for "all items less food and energy." This statement asks if there was NO CHANGE from May through September. We can see from the table that there were 3 "changes" (in May, June and July), so the answer to this question is NO.

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

Hello Rich,

Thank you very much for the excellent explanation.

Best Regards,
Sri

gmattesttaker2 wrote:Hello,

For Question 2 here, I am thinking that CPI-U for electricity in July was 0.5 and in August it was 0.7 due to the 0.2 increase. Hence, %age increase is 40%. Is this correct?

For Question 3, the OA says that there was change in the CPI-U from May 2010 to Sep. 2010. Since it is 0 for May and Sep 2010 I was not clear. Can you please explain this?


OA: Yes No No

Thanks a lot,
Sri

I hated this question, since I got it wrong. The reason I got it wrong was the wording of the question. It clearly states ' For each following, select YES if the statement is INFERABLE from the given information. ' So basically, I thought it was like Data Sufficiency where we didn't need to solve it, and see if we have the information to solve it. So for the first question, I clicked yes instead of no, since there's information that you can obtain from it to get the right answer.

Hello Rich
Small confusion.

For each following, select YES if the statement is INFERABLE from the given information else select NO.

Shouldnt answer be YES for all these 3 answers. Its not a true false question. It just asks you if the information is sufficient to answer these.

crescendo85 wrote:Hello Rich
Small confusion.

For each following, select YES if the statement is INFERABLE from the given information else select NO.

Shouldnt answer be YES for all these 3 answers. Its not a true false question. It just asks you if the information is sufficient to answer these.

"Inferable" and "sufficient to answer" are not the same thing. Take a simple example. Say x = 9. This would be sufficient to answer the question "Is x prime?" However, if we were asked, "Can we infer that x is prime?" the answer is "no," we can't. So to summarize: Sufficient = we definitively know the answer to the question. Inferable = we can deduce that the statement in question is true.

See here for another example in which a test-taker was struggling to differentiate between inferable and sufficient - this may help clarify the distinction: https://www.beatthegmat.com/ir-inferenc ... 88804.html

Thanks for prompt reply
Its better now. Cant they just ask us "Is it true or false"
But well noted. You mean read inferable as true except cases where there is no way to find this information from table - in that case say False.

I had the same problem with this question in regards to the phrasing of "yes if the statement is inferable from the given information." I don't agree with the wording but I'll accept it. Thanks for the clarification.

What we see: a Table Analysis question. Every number in the table is a change from the month before, not a price level. That one fact settles all three statements.

Step 1. Read the table's header before any number.
What we see: the columns sit under "Seasonally adjusted changes from preceding month."
What it means: 0.3 under Jul 2010 means prices rose 0.3% from June to July. A 0 means prices did not move that month. A negative number means prices fell.
What we do and why: hold this in mind for each statement. Most mistakes here come from treating these numbers as index levels.

Step 2. Statement 1: did "All items" vary more month to month than "All items less food and energy," March to September 2010?
What we see: All items: 0.1, -0.1, -0.2, -0.1, 0.3, 0.3, 0.1. All items less food and energy: 0, 0, 0.1, 0.2, 0.1, 0, 0.
What it means: the first row swings from -0.2 to 0.3, a spread of 0.5 points, and flips between rising and falling. The second stays between 0 and 0.2 and never falls.
What we do and why: "All items" clearly moves around more. Yes.

Step 3. Statement 2: did electricity's CPI-U rise 0.5% from July to August 2010?
What we see: Electricity shows 0.5 under Jul and 0.2 under Aug.
What it means: the Aug number is the change from July to August, so the rise was 0.2%. The 0.5 is the rise from June to July.
What we do and why: the statement grabs the wrong month. No.

Step 4. Statement 3: was there no change in "All items less food and energy" from May to September 2010?
What we see: after May, that row shows 0.2 for June and 0.1 for July.
What it means: prices rose 0.2% in June and 0.1% more in July. August and September show 0, so they held still, but the level in September is higher than in May.
What we do and why: the index changed. No.

The trap: Statement 3. Seeing 0 in both the September column and nearby columns makes it look like nothing moved. But each cell is one month's change; the months in between add up.
Faster way: for "from month X to month Y," add the cells after X through Y. Here \(0.2 + 0.1 + 0 + 0 = 0.3\), not 0.
Takeaway: read the column header first. A table of changes answers "how much did it move that month," and a stretch of months needs the changes added together.

Answer: Yes, No, No