Markov chains

[NE2000]

I came across those questions where it asks you to find out the number of people in group A and group B 4-5 months from now where the current month is labelled i and you seek to find the numbers in i + 4 or so. However, I found it pretty time-consuming with full working and as MathsQuest are known for elaborating on the steps involved at times, does anyone have any shorter way of doing it than doing it one month at a time? Thanks

Also, just another thing, whenever we come across a probability question where the question doesn't define X for you, should be defining X just to be sure or should you just label X as the particular distribution you are looking at and just continue on. I've been defining X but the textbook examples haven't so I just wanted to check.

[Rebecca.tutoring]

Are you doing CAS? If you are, you can use matrices to work out those kinds of questions.

Also, just another thing, whenever we come across a probability question where the question doesn't define X for you, should be defining X just to be sure or should you just label X as the particular distribution you are looking at and just continue on. I've been defining X but the textbook examples haven't so I just wanted to check.

I'm not sure what you mean by "label X as the particular distribution you are looking at"... But basically, you're right - you should always define variables ("Let X be the event that it rains").

[NE2000]

Are you doing CAS? If you are, you can use matrices to work out those kinds of questions.

Also, just another thing, whenever we come across a probability question where the question doesn't define X for you, should be defining X just to be sure or should you just label X as the particular distribution you are looking at and just continue on. I've been defining X but the textbook examples haven't so I just wanted to check.

I'm not sure what you mean by "label X as the particular distribution you are looking at"... But basically, you're right - you should always define variables ("Let X be the event that it rains").

nup I'm not doing CAS but the book has some stuff on matrices that I sort of skipped owing to tiredness but I'll look over it again. And yeah thanks for the clarification.

[Glockmeister]

I dont think normal methods actually has matrices in the study design, so you dont have to learn it if your are bit iffy about it.

[Roflmao]

I think i have heard of this

[Mao]

I think i have heard of this

knowing Ahmad, you probably have..

[Mao]

I came across those questions where it asks you to find out the number of people in group A and group B 4-5 months from now where the current month is labelled i and you seek to find the numbers in i + 4 or so. However, I found it pretty time-consuming with full working and as MathsQuest are known for elaborating on the steps involved at times, does anyone have any shorter way of doing it than doing it one month at a time? Thanks

The only straight forward way is through matrices, and it really isn't that hard. I have a short guide on matrices somewhere in the notes section, you'll find it under methods [it covers a few other things for CAS, you don't necessarily need to know them, but they can become useful]

Otherwise, giant massive stupid tree diagrams are for you.

Also, just another thing, whenever we come across a probability question where the question doesn't define X for you, should be defining X just to be sure or should you just label X as the particular distribution you are looking at and just continue on. I've been defining X but the textbook examples haven't so I just wanted to check.

If you find defining X works better for you, then by all means go ahead and do so, but I do believe they accept both of the following forms:

Pr(X=4)=....
Pr(4 heads)=...

I personally find the latter easier [saves me defining stuff]. Since in VCE you only learn univariate probability, it isn't THAT necessarily to define it.

[NE2000]

Right thanks everyone.

Just another point, do we need to know the equation for a normal distribution curve or just know how to find probabilities using the standard normal distribution? Also, do we get the cumulative normal distribution table for the tech free and tech active exams?

[kurrymuncher]

 You dont get the table for normal dist in the tech free or tech exams. Because there was no normal distribution last year, Im guessing there will be this year, so just remember the normal distribution curve equation anyway, although I doubt that there will be any questions on it in the tech free exam.

or just know how to find probabilities using the standard normal distribution?

You must know how to do this.

[NE2000]

or just know how to find probabilities using the standard normal distribution?

You must know how to do this.

Yeah of course, given that there's like two exercises dedicated to doing it in my textbook

[kurrymuncher]

What book are you using?

[NE2000]

MathsQuest

[pHysiX]

since you ain't doing methods cas, don't stress too much about markov chains.

they are real easy. don't worry. markov chains is just about being bothered to plot the info into a 2/3 stage tree diagram. if i were u, i'd focus on binomial stuff. well that's how i found normal methods anyway =]

[NE2000]

since you ain't doing methods cas, don't stress too much about markov chains.

they are real easy. don't worry. markov chains is just about being bothered to plot the info into a 2/3 stage tree diagram. if i were u, i'd focus on binomial stuff. well that's how i found normal methods anyway =]

They weren't necessarily hard, just really time consuming, I just needed to check whether MathsQuest had missed some shortcut. Thanks anyway