VCE General & Further Maths Question Thread!

[korng]

how's to prepare for further math first SACs ? 

[AngelWings]

how's to prepare for further math first SACs ? 

It depends on how you like to revise for Maths usually. Oh, and probably how you like making cheat sheets.

In a further core sac are we suppose to draw residuals/ scatterplots and all those other charts accurately? It just seems too time consuming tbh

Not necessarily. Further teachers are usually kinder and will usually put that sort of question either on the technology section (but still draw the whole graph to an approximate scale) or have less data (i.e. probably 15 points at most) to plot by hand with accuracy. It mostly depends on the person who's making your SAC though, so this could be wrong altogether. Just expect the worst and be prepared to draw any of them (but nothing too ridiculous, it still has to be doable). 

[TheAspiringDoc]

I'm just not getting this 'without solving for the pronumeral, solve this equation' stuff..
This probably looks like child's play to you guys but could someone please show me how to do this (with full workings)
If 6a=2a+10, find the value of 13-2a without solving for a.
  Thanks

[keltingmeith]

I'm just not getting this 'without solving for the pronumeral, solve this equation' stuff..
This probably looks like child's play to you guys but could someone please show me how to do this (with full workings)
If 6a=2a+10, find the value of 13-2a without solving for a.
  Thanks

If you can solve for a variable, you can do this stuff. However, instead of trying to make weird operations until you get to a single thing, you're doing weird operations to get to a complicated thing.

So, first thing we notice about the 13-2a? a is by itself, so let's work with that:



Next thing? There's a -2 in front of the a, not a 4, so we change that. How do we get from 4 to -2? Divide by -2:



Finally, what's left in what they told us? +13, so let's add in 13:



And we're done.

[TheAspiringDoc]

Thanks for the speedy reply EulerFan101, but I'm warning you, if you continue to be this helpful, I'm going to have to change my username to EulerFanFan 

[Escobar]

in my textbook it says
in a negatively skewed boxplot, the median occurs further towards the right end of the box & left tail is longer
and in a positively skewed boxplot, the median occurs further towards the left end of the box & right tail is longer
but
i saw a facebook post
https://www.facebook.com/photo.php?fbid=969678223063087&set=gm.431048803739825&type=1&theater

if you can't see it, the image is here: https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xtf1/v/t1.0-9/11068300_969678223063087_3082187454809633619_n.jpg?oh=6683a0ed2ec77dced1089faf04e17683&oe=556FDC74&__gda__=1434052399_0a8b94eb1f21a4a3a4559be9324620dc
the comments are all saying it is positively skewed
but, the median is towards the right of the box, which is not a characteristic of positive skew (according to textbook)
so
is my textbook wrong
or is the boxplot not positively skewed & are all the comments wrong
lol

[bae]

in my textbook it says
in a negatively skewed boxplot, the median occurs further towards the right end of the box & left tail is longer
and in a positively skewed boxplot, the median occurs further towards the left end of the box & right tail is longer
but
i saw a facebook post
https://www.facebook.com/photo.php?fbid=969678223063087&set=gm.431048803739825&type=1&theater

if you can't see it, the image is here: https://fbcdn-sphotos-b-a.akamaihd.net/hphotos-ak-xtf1/v/t1.0-9/11068300_969678223063087_3082187454809633619_n.jpg?oh=6683a0ed2ec77dced1089faf04e17683&oe=556FDC74&__gda__=1434052399_0a8b94eb1f21a4a3a4559be9324620dc
the comments are all saying it is positively skewed
but, the median is towards the right of the box, which is not a characteristic of positive skew (according to textbook)
so
is my textbook wrong
or is the boxplot not positively skewed & are all the comments wrong
lol

My textbook also says the same thing, negatively skewed = median further to right & left tail longer, positively skewed = median further to left & right tail longer. Your textbook says that it's negatively skewed, but I think because of the outlier on the right the boxplot is therefore positively skewed, like all the other comments. 

[stunfiskery]

I've just received the results for my first Further Maths SAC. It was on Graphs and Relations (it was out of 40) and I just have a question on how my marks will be conveyed to VCAA. Hypothetically speaking, let's just say I got 97.5% and the SAC accounts for 20 VCAA marks. Of that how many VCAA marks would I get? 20? 19.5? Is it in the same ratio. For example is a 36/40 equivalent to 18/20 VCAA marks?

[keltingmeith]

I've just received the results for my first Further Maths SAC. It was on Graphs and Relations (it was out of 40) and I just have a question on how my marks will be conveyed to VCAA. Hypothetically speaking, let's just say I got 97.5% and the SAC accounts for 20 VCAA marks. Of that how many VCAA marks would I get? 20? 19.5? Is it in the same ratio. For example is a 36/40 equivalent to 18/20 VCAA marks?

It entirely depends on how your school has structured your SACs.

[chansena]

Hi ALL!

What would i comment on this box plot. it is from chocolate sales in one month. I get confused with what to say. Other than the skewness my teacher has said to relate it back to the scenario in this case it is cholcate production but how do i relate it

[keltingmeith]

Hi ALL!

What would i comment on this box plot. it is from chocolate sales in one month. I get confused with what to say. Other than the skewness my teacher has said to relate it back to the scenario in this case it is cholcate production but how do i relate it

What's the range of sales? How about the median? What does the median suggest? Any points in there that we can't really consider? Why/why not? How spread out is the data? What does this suggest in the variation of chocolate sales each month?

[chansena]

What's the range of sales? How about the median? What does the median suggest? Any points in there that we can't really consider? Why/why not? How spread out is the data? What does this suggest in the variation of chocolate sales each month?

The data is a  positive skew. The range of sales varied from 355  to 601 with one massive sale in chocolates with 906 in sales.

What does the median mean in a sales in a situation like this ? Would it mean most of the sales was at around the 461.5

[AngelWings]

The data is a  positive skew. The range of sales varied from 355  to 601 with one massive sale in chocolates with 906 in sales.

What does the median mean in a sales in a situation like this ? Would it mean most of the sales was at around the 461.5

Well, consider this. What occurs to a mean when there's an outlier?

Spoiler

The mean is altered, drastically, as all the data is used to calculate an average.

Is the mean reliable in data where an outlier exists?

Spoiler

No, since the mean uses all the data.

What are the measures of centre that would be relevant to this data?

Spoiler

We know that there's the mean, median and mode. We've worked out that the mean would not be as accurate to find the centre in this data and the mode would probably be pointless, thus we're left with the median, which finds the middle number, without having to use all the data in its calculations.

[chansena]

Cant decide which type of graph this would be for time series

Seasonal Pattern
Cyclical Pattern
Random
Downward / upwards trend


I'm tipping its a random but i just wanted more opinions on it

Thanks !

[StupidProdigy]

Can anyone explain how you get the answer in Question 5 of vcaa Exam 1-2005? Thankyou!