VCAA EXAM 2 2009 CORE

[bbabe]

hey guys, i was having trouble figuring out why the answer is what it is for question 4.c of core.

the question states: table 2 shows the seasonal indices for rainfall in summer, autumn and winter.
summer: 0.78
autumn:1.05
winter: 1.07

what does the a seasonal index of 1.05 tell us about the rainfall in summer?
the answer is the autumn rainfall is 5% above the average for the four seasons of the year.

A common incorrect answer suggested that the autumn rainfall was 5% above the monthly average. 

i was just wondering why its the average for the four seasons rather than the monthly average?

thanks

[CW16]

Because Autumn is a season, rather than a month. Meaning that it is 5% over the season averages of the 4 seasons.

[astone788]

i was taught that a seasonal index of 1.05 tells its its 5% higher than the monthly average. So who knows.

[brenden]

Well the data is concerned with the seasons and not the months. Tere are tree months in summer and the index is concerned with summer as combines those months, thus season.
Also, to find sprig, you would add those three up and subtract the sum from 4, as there are four seasons. If it were to do with months you would divide by 12.

[bbabe]

ahhhh of course! i feel so silly now lol

so if i replaced 'four seasons of the year' to just autumn, will that still be correct?

[Stick]

"The autumn rainfall is 5% above the average for autumn." That doesn't really make sense.

If you're looking for a copy/paste answer (not that I recommend it) just use the term "the average for all seasons combined". A lot of students have referred to sales in their seasonal indices answers, when the question doesn't even relate to sales, so be careful.

[astone788]

replace it with seasonal average

[bbabe]

alright thanks guys

my head was about to explode!