Probability SAC

[KiNSKi01]

yooooo

When it comes to probability unit, what are some of the hardest types of questions we might get. (I have sac for probability coming up)

Also are there any general things that one should look out for/ be careful of (e.g whether or not a boundary is inclusive when doing binomial distribution)

thanks!

[AlphaZero]

yooooo

When it comes to probability unit, what are some of the hardest types of questions we might get. (I have sac for probability coming up)

Also are there any general things that one should look out for/ be careful of (e.g whether or not a boundary is inclusive when doing binomial distribution)

thanks!

Just to quick question, has your school actually completed Unit 3 Methods already? Or, is your school completing VCE in the northern-hemisphere timetable? If not, I'm quite surprised that you're doing a probability SAC this early considering the study design says it must be done in Unit 4.

Nonetheless, here is some general advice regarding Area of Study 4.

1) Make sure you answer the question fully and give your answer in the required form. This sounds like a 'no-brainer', but in fact, students incorrectly reading questions is very common. The most common mistake is not giving your answer in the required form, especially in probability. If the question states to give your answer as a percentage correct to two decimal places, then you will only get the answer mark if you do this.

2) Inequality sign usage. You mentioned this before: given any discrete random varible \(X\), in general,  \(\text{Pr}(X<k)\neq\text{Pr}(X\leq k)\). Also, it's important to understand what your calculator is doing in certain calculations. A common mistake is thinking that  \(\texttt{binomCdf(n,p,a,b)}\) corresponds to  \(\text{Pr}(a<X<b)\),  where  \(X\sim \text{Bi}(n,p)\).  (Clearly inequalities are less important to continuous random variables since given a continuous random variable \(Y\),  we have \(\text{Pr}(Y=k)\equiv 0\)).

3) Notation and communication. It is super important that you are using the correct terminology and notation in your responses. It is too often where students use calculator notation to communicate their answers. This is wrong. Further, there are many students that confuse \(\hat{P}\) with \(\hat{p}\) and similar ideas.

To be honest, I could go on and on forever, but I would be repeating mostly what has been said in VCAA exam reports. The best way to learn about the common errors students make is to either make them yourself (and not do them again), and read about them in the examination reports.

[KiNSKi01]

thank youuu very much! Ur a legend.

My school already did Unit 3 in the last half of 2018. Effectively the the whole methods course was shifted forwards a semester.

So we r gonna have an extra long revision period before the exams 

[S_R_K]

thank youuu very much! Ur a legend.

My school already did Unit 3 in the last half of 2018. Effectively the the whole methods course was shifted forwards a semester.

So we r gonna have an extra long revision period before the exams 

Did you do any SACs in 2018 that contribute towards your 2019 study score?  It's a breach of VCAA's assessment policies to do any SACs outside of the academic year in which Units 3 & 4 are completed.

[AlphaZero]

thank youuu very much! Ur a legend.

My school already did Unit 3 in the last half of 2018. Effectively the the whole methods course was shifted forwards a semester.

So we r gonna have an extra long revision period before the exams 

Did you do any SACs in 2018 that contribute towards your 2019 study score?  It's a breach of VCAA's assessment policies to do any SACs outside of the academic year in which Units 3 & 4 are completed.

It's completely okay for teachers to deliver content early (nothing wrong with accelerating students), but assessments cannot be taken outside of their allocated semesters.

Echoing S_R_K's question:  Did you do any Unit 3 SACs that will contribute to your before the academic year started?

[KiNSKi01]

Ahahaha no just did the content early. Yeah sorry I probably didn't make that clear. Most content got shifted forward but this probability sac will be the first one to contribute to SS 

I think the reason behind it is because of a strong cohort and it would be more beneficial to introduce the content earlier