ATAR Notes: Forum
Archived Discussion => 2010 => End-of-year exams => Exam Discussion => Victoria => Further Mathematics => Topic started by: ryanlp1 on November 01, 2010, 05:47:27 pm
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Hey could somebody please explain to me why the answer is B and NOT C ?
I still don't quite get it.
Thanks =]
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Because you have to use the 68%/95%/99.7% rule (almost the same as range/8) and not range/4
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Because you have to use the 68%/95%/99.7% rule (almost the same as range/8) and not range/4
yeah, you find the amount of units to each side to give you within the 68%, or 34% on one side, and see that it was about 2, hence the SD is 2.
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if you got the standard deviation formula from essentials maths book, it is wrong. the formula should be (range)/6. i remember covering that section at the start of the year and my teacher told us to fix it.
and also there was a similar question 2001 exam 1 Q6. doing range/6 gives the right answer, but range/4 doesnt. might wanna check it out.
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Wahahah, the only SD formula I found in MQ was the one used for S+L plots and I used one from bound notes here (which I hear came from essentials)...argh...so unfair...
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How come Core Q 1 was D? not E?
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You most likely counted the bar for 178 degress...I did too...
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Y cant we do that though?
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Y cant we do that though?
I did that wrong too.
It's because it says 179-181.
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:(
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I don't think this question is fair on those who used the Essential Math book :/ because it clearly states that range / 4 = standard deviation.
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I don't think this question is fair on those who used the Essential Math book :/ because it clearly states that range / 4 = standard deviation.
Hence why the essential book is a piece of shit for further maths...
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thats an estimate though ^
clearly states "using the 68-95-99.7% rule"
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thats an estimate though ^
clearly states "using the 68-95-99.7% rule"
shit estimate. it should be range/7 really.
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thats an estimate though ^
clearly states "using the 68-95-99.7% rule"
Can you explain this formula to me? because under the "68-95-99.7% rule" in the Essentials book, all it talks about is the curves/mean/bottom percentages etc.
Oh and does anybody think vcaa will take this question into consideration when marking it?
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thats an estimate though ^
clearly states "using the 68-95-99.7% rule"
Can you explain this formula to me? because under the "68-95-99.7% rule" in the Essentials book, all it talks about is the curves/mean/bottom percentages etc.
Oh and does anybody think vcaa will take this question into consideration when marking it?
VCAA knew that, they just wanted to you use it in a different way. Test if you really understood the concept. I very much doubt they'll accept C
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I don't think this question is fair on those who used the Essential Math book :/ because it clearly states that range / 4 = standard deviation.
What a load of crap, purposely creating a question a large group of students will get wrong simply due to the fact that they are lead to believe a certain formula should work with no real way of figuring out that said formula was wrong...
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But it said using that specific rule so you have to use the thing where there's 3 standard deviations on each side of the mean.
But yes i hate vcaa.
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They wont accept c because, there was a question like this in the 2001 exam and most people back then also did range/4. they didn't accept that answer. If they do accept it now it won't be fair for those in the past.
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i just used the bell shape curve, as you had the upper quartile of 1.5 away from the mean, as SD1 is 34% not 25% you need to add a little extra to 1.5, then you end up with 2
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This is how I did it:
The fact that the boxplot was approximately symmetric or thereabouts, rendered the mean to be approximatelysimilar to the median (which could be easily determined). With this in mind, find the range of the boxplot (approximately 12). Split the range into six components (as there are six components in the bell-shaped curve which are the three standard deviations above and below the mean) and you get an answer of 2. The reason I split the range was because 99.7% is approximately equal to 100% (which accounts for all my data values).