VCE Methods Question Thread!

[Umar but with O]

Is the study of matrices in units 1/2 required for units 3/4 (methods)?

[Sine]

Is the study of matrices in units 1/2 required for units 3/4 (methods)?

I think most schools go into matrices in more depth in units 1/2 than what is actually required for 3/4.

For 3/4 the importance of matrices lie with transformations however it is probably safer to revise addition/mutiplication/inverse of matrices as well.

[eloisegrace]

Anyone know if continuous random variables are still in the course or not (i.e ch 15 of Cambridge)?

Nope, only discrete, binomial and normal variables. No stats either

[The Cat In The Hat]

Hi Guys,

Could someone please help me with the attached questions, im so clueless with how to do them.

Cheers

Hi and welcome to AN! Could you please put the question/s up in full? All I see is a short sentence and no context.

[The Cat In The Hat]

Since we have no idea about what programs these are, they cannot be answered. Could you put in the entire question please?

[The Cat In The Hat]

The probability that a new puppy qualifies for the scent training program is 1/3 and the probability that it qualifies for the guide dog program is 1/4.
g) If a puppy cannot qualify for both programs, what is the mathematical term that represents this situation?

It can qualify for one or the other, so they are mutually exclusive.

[Sine]

Hi Guys,

Was wondering if anyone would please show me how to do this question and provide solutions.

Thanks in advance!

What aspect of the question are you having difficulty with? What have you tried so far?

Also, please try to refrain from double posting in the future.

[Sine]

The whole question, i am very unsure. My methods skills are pretty bad. Thanks so much for your time Sine.

Alright, I'll start with your first post and try to put you on track.

The questions says the time to complete the workout is normally distributed with a mean of 30 minutes and a standard deviation of 2 minutes.

This should be a very clear sign that you need to define the random variable T.

So, T ~ N(30,2²) or T ~ N(30, 4). Is this notation familiar?

If you want to find the probability that she takes less than 25 minutes to finish her work out use the random variable T.

Pr(T < 25)
To solve this you convert it to a standard normal distribution with a mean of 0 and standard deviation of 1 (Z ~ (0,1))
Pr(T < 25) = Pr (Z < (25-30)/2)) = Pr(Z < -2.5)

[rukayabal]

Hi all,
I would like to know whether combinatorics and permutations and all the factorial skills need to be known for the current study design as I am completely clueless about them. I saw a question in the 2019 nht exam 1 and seems incredibly complicated. Here it is. I have attached it.

I would really appreciate a reply.

[S_R_K]

That exam question is from the current study design, so yes.

[keltingmeith]

Hi all,
I would like to know whether combinatorics and permutations and all the factorial skills need to be known for the current study design as I am completely clueless about them. I saw a question in the 2019 nht exam 1 and seems incredibly complicated. Here it is. I have attached it.

I would really appreciate a reply.

Just adding on to what S_R_K has said - these questions also aren't too difficult, don't be scared just because they're technically in the realm of combinatorics. Remember - this is just a binomial distribution problem, all you need to do is apply the binomial distribution material as you were taught it in class.

[rukayabal]

That exam question is from the current study design, so yes.

Just adding on to what S_R_K has said - these questions also aren't too difficult, don't be scared just because they're technically in the realm of combinatorics. Remember - this is just a binomial distribution problem, all you need to do is apply the binomial distribution material as you were taught it in class.

Thank you 

[emonerd]

For this graph here, would you say it's strictly increasing over the interval (0,1) and (3,5) OR [0,1] and [3,5]? I'm just a bit confused about whether we include cusps and endpoints.

thanks 

[keltingmeith]

For this graph here, would you say it's strictly increasing over the interval (0,1) and (3,5) OR [0,1] and [3,5]? I'm just a bit confused about whether we include cusps and endpoints.

thanks 

Note that definition of strictly increasing/decreasing has NOTHING to do with the derivative - and as a result, you DO include end-points.

A function is strictly increasing over an interval if for every b>a on that interval, f(b)>f(a). Let's consider the point x=1 - in this case, b=1, and f(b)=1. Pick whatever you want for a. If a=0.5, f(a)=0.5<f(b). We can include 0.5 in that interval. In fact, no matter how close a gets to x=1 (or the limit as a goes to 1), f(b) is always going to be bigger. "But keltingmeith", you say, "this explanation means it would be an OPEN interval, not a closed one!" And the answer to that is it doesn't make sense to check for when a=b - because of course f(b) is not going to be bigger than f(b), they must be the same. As a result, the mathematical community basically just decided that it's okay to include end-points, and so that's what people do. Kind of frustrating explanation, I'm sure, but it is what it is.

[TheEagle]

For this graph here, would you say it's strictly increasing over the interval (0,1) and (3,5) OR [0,1] and [3,5]? I'm just a bit confused about whether we include cusps and endpoints.

thanks 

As a rule of thumb, include endpoints for strictly increasing/decreasing. However, if is is asking for just increasing/decreasing, then do not include the endpoints.


Hence, in this case, include the endpoints, i.e. [0,1] and [3,5].


If you want the proof, I believe Tal from Edrolo has linked a bulletin which was released by VCAA back in 2011 explaining the difference, though, the proof itself isn't really needed.