VCE General & Further Maths Question Thread!

[death to the vcaa]

Thank you so much. That's reassuring. I appreciate it man 

[Cristiano]

Hi, can someone please explain how to do this recursion question? I don't get how you can go from u(n+1) to u(n-1). Thank you

We know that so we must find the second term. Using the equation,    

= 2 × -3 -1


So, the answer is E, as it is the only choice with the second term being -7 

[chenay0123]

Thanks plato and Cristiano for the replies!

[minerva]

Hi, can someone please help me with "How does an outlier affect the r value (correlation coefficient)?"

[MightyBeh]

Hi, can someone please help me with "How does an outlier affect the r value (correlation coefficient)?"

Remember that r is for classifying the strength of a linear relationship, and it's calculated using every point of data that you have. On top of that, the mean and the standard deviation are both pretty heavily affected by outliers (mean will be much higher/lower, standard deviation will be really high when it shouldn't) so the correlation coefficient is pretty useless if you include outliers.

* you don't need to know this equation

Graphically, this means that the line won't actually be the closest fit to the data because it'll be 'pulled' toward the outlier.

This one's without outliers


This one has an outlier

[YellowTongue]

How would you describe a time series trend using "general terms"?

[clarke54321]

How would you describe a time series trend using "general terms"?

Hey,

I would think that you would just say something along the lines of 'this time series shows an increasing or decreasing trend.'

[Seņor]

How would you describe a time series trend using "general terms"?

Im not sure if this is what you are looking for...but if you mean about a general line going upward or downwards then it is a Secular upward/downward trend.

[minerva]

Hey guys, how do you know if a scatterplot has an outlier? Are you meant to be able to tell simply by looking at the scatterplot or can the correlation coefficient indicate the presence of an outlier/s?

[clarke54321]

Hey guys, how do you know if a scatterplot has an outlier? Are you meant to be able to tell simply by looking at the scatterplot or can the correlation coefficient indicate the presence of an outlier/s?

Hi,

As far as my knowledge goes, I think that you are only able to tell if there is an outlier by observation. I haven't actually learnt of any calculation which is able to detect an outlier in a scatterplot.

[ayesha2011t]

Hey guys, how do you know if a scatterplot has an outlier? Are you meant to be able to tell simply by looking at the scatterplot or can the correlation coefficient indicate the presence of an outlier/s?

Hey Minerva,
Just to add on to Clarke, I believe it is a bit of both. What I usually do is doing 2 calculations to find the correlation coefficient; one with outlier and one without. If your coefficient shows an extreme change than you are 100% confident that it is an outlier. This method just gives you that extra oomph in knowing you're right :')

[clarke54321]

Hey Minerva,
Just to add on to Clarke, I believe it is a bit of both. What I usually do is doing 2 calculations to find the correlation coefficient; one with outlier and one without. If your coefficient shows an extreme change than you are 100% confident that it is an outlier. This method just gives you that extra oomph in knowing you're right :')

That's really effective, I never though of that 

[chenay0123]

Hi, can someone tell me how to do this question without listing out all the terms? Thank you

[ayesha2011t]

Hey guys, does anyone know how to use the TI-Nspire CAS functions for financial maths (amortisation table, etc)? If so, pls let me know as I have my sac on Friday and am totally lost.

[friedchromosome]

Hey guys, seeing as financial maths is apart of statistics now, i could really use some pointers as to where i can gain the most practise from for these 2 chapters, if anyone has some worksheets please message me !!!!! thanks