VCE General & Further Maths Question Thread!

[MagicGecko]

Nope as far as further maths is concerned, the use of the log transformation and knowing that it compresses your data values is about as far as it goes. Though that's for the core, my school only did number patters, business and matrices and we didn't touch logs after the core but I can't say the same for the other modules which I didn't do. But I highly doubt you need to know about the logarithms to the extent in methods, just the basics i'd say.

[Einstein]

Our further teacher is also a spesh teacher at our school, he said it wasn't needed, but he did give us a quick recap incase the exam asked for y=.... and not logy=.....

just getting rid of log and putting it to the base of 10 or something like that.

[Einstein]

kinda like getting rid of the squared in

[~V]

The only other way I can see you calculating the residuals without  reading from the graph is if the question also gives you a set of actual values. Which you would then use to create a regression line. From there its simply the case of
residual value = actual value - predicted value
Though I am quite sure you won't be asked to determine the residual from the graph alone, especially if its hard to make out the points (I haven't crossed any questions that do this...well at least none come to mind).

And no they are not the same.
A log₁₀(y) is called a log transformation whereas a 1/y is called a reciprocal transformation.
Basically they serve the same purpose, its just that the reciprocal transformation compresses the data to an even greater extent than the log transformation.

hope that cleared some things up somewhat

Cheers MagicGeko, it was a multiple choice question for my practice test and it was really hard to accurately pinpoint the co-ordinates of all the points :/ but looking through practice exam questions they all supplied a table of values . When you are asked to use 3 median method and given a table of values, do you have to reorder the points so they're lowest to highest? Also, how/what do you analyse for percentaged segmented bar charts in order to get full marks?

[The Brightest Witch]

When you are asked to use 3 median method and given a table of values, do you have to reorder the points so they're lowest to highest?

Yep! You reconstruct the table so that the x-values are from lowest to highest, but still have their corresponding y-values (so their y-values move with them). Then in each of your 3 sections separately, you order your y-values from lowest to highest. Finally, you get a median x-value and a median y-value from each of the 3 sections

In the example below, our 3 points are: (3.5,8.5) , (7,4) , and (11,7.5).

[lilellanii]

Hey Guys :3

Just wondering, when describing a seasonal trend, would you mention values?  Or just like, when there are peaks and troughs?

Thanks xx

[Sense]

When you're making a box plot from a frequency table that has classes (100- ,200-, 300-) instead of specific numbers, do you use the middle number like 100- would be 150 ?

[Sense]

Anyone ?

[~V]

When you're making a box plot from a frequency table that has classes (100- ,200-, 300-) instead of specific numbers, do you use the middle number like 100- would be 150 ?

You have to estimate the 5 point summaries. This is a good video showing you what to do

[Einstein]

how do we find the linear regression formula from a graph/scatterplot?

[~V]

how do we find the linear regression formula from a graph/scatterplot?

Write down the x and y co ordinates of each points of your scatterplot/graph. Then put it in the CAS--> list and spreadsheets then linear regression line.

[Einstein]

I've tried that before didn't get similar to the one with data.

[~V]

Can you post a picture and i'll try to do it?

[Sense]

You have to estimate the 5 point summaries.

Okay, so if I'm using this table and it asks me to find the min-q1-median-q3-max of the high dosage group, would I just use the median ( ( Median = x) of the interval or the actual interval (Median = x - x)

[~V]

Okay, so if I'm using this table and it asks me to find the min-q1-median-q3-max of the high dosage group, would I just use the median ( ( Median = x) of the interval or the actual interval (Median = x - x)

i reckon you use the midpoint of the intervals. I don't know if i'm doing it right but.. i think the median is (226+1)th number, 113.5th number, so its the 800- gram interval? And for Q1, its (113.5+1)th number, 57.25th number, so its 700- gram interval? And for Q3, its (113.5+1)th number, so 57.25th number but ABOVE the median, so its still in the 800- gram interval? Min=600- and max=1000-. i dont even know. What is the answer though?