# Simple price indices question

If the inflation indices was reset to 100 in the the 3rd quarter, what would be the fourth quarter inflation index for food. I have no idea how to do this . Below is the graph:

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## migrated from math.stackexchange.comSep 7 '12 at 5:22

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This was closer to on-topic on math.stackexchange than it is here. Not every aspect of every statistic is a statistical issue. You need to know the definition of an inflation index from economics, and then it is a simple calculation. Is this a homework question, and has your textbook covered how inflation is calculated? By the way, the word "indices" is the plural of index. –  Douglas Zare Sep 7 '12 at 5:39
Those are presumably price indices rather than inflation indices. –  Henry Sep 7 '12 at 6:56
@Henry Could you be so kind to change the title of the question appropriately ? I think I am not qualified, but "Simple Statistics Question" is terrible. –  steffen Sep 7 '12 at 8:31
@DouglasZare Assuming that the unedited spelling was "indexes", then "indexes" actually gets a lot of use in economics literature. Quick browse of English forums on this matter reveals that both are correct. –  user13253 Sep 7 '12 at 14:13
@Shaniqueia: The point I was making was not about how to spell the plural, but not to use it as a singular. Anyway, you can see that the spelling wasn't changed in Henry's edit by clicking on the time of the edit. –  Douglas Zare Sep 7 '12 at 23:04

If the index was reset to 100% at the 3rd quarter, the 4th-quarter index would be $94\% / 95\% \approx 99\%$.