Separate names with a comma.
Absolutely you can - in fact I recommend it to my students to save time.
It's always helpful to post a screenshot of the exam question to help others help you. The 0.264 is the complete linear predictor for a female...
Yes, such a culture would mean that newbies would never learn anything, which would lead to more mistakes. So it's bad management and if you find...
Theta is a function of the mean of the distribution. Phi is the "other" parameter - in this case, sigma. Hence, the c(y,phi) function should only...
Paper B is covered in the Paper B Online Resources (PBOR) which is included in your purchase of the Combined Materials Pack (CMP). The online...
Since even "calculate" questions now require working in the online exams, you will NOT receive full marks. You might get the answer mark but none...
I'm assuming you just calculated each of them the long-winded way and got the same answers. In which case you would have got the marks - it just...
The issue is the name you are using in the data.frame does not match the name used in the lm function. Hence, the predict function has no idea...
App still works, but it's not available for iphones. Certainly students have been passing around the "CP1 Acronym" excel spreadsheet - so might...
Re-read the question, it doesn't say Exponential distribution with parameter 2.
The statistician has made a mistake - that's why you are asked to calculate the actual value in part (iii) and then comment on why the...
Remember the posterior is proportional to the prior multiplied by the likelihood. That's why the parameters are not matching the likelihood on its...
Yes, that's a standard abbreviation and so markers will know what it means. If you use something non-standard then do define it.
Yes, so if you store the observed frequencies in "obs" and the expected frequencies in "exptd" then recall the formula is: \(\sum...
The built in chisq.test function doesn't work well here as it doesn't correctly calculate the degrees of freedom when you fit a model - so you...
They're in your Paper B online classroom (PBOR) that you got access to when you purchased the CMP.
Happy to help.
\(var(X - Y) = var(X) + var(-Y) = var(X) + (-1)^2 var(Y) = var(X) + var(Y)\) Intuitively, if you have two distributions with the same spread, you...
I'm not sure what benefit my opinion is, when it's the examiner's opinion that counts! When you get your results back later this month, you can...
As I said - your approach loses valuable information - so you will lose marks.
Truncating the distribution loses valuable information. So keep the more than 3 but treat them as 3. This will give a lower limit.
Updating your version of R can also resolve this issue.
The whole point of multichoice questions is to avoid you having to type complicated maths in Word. So do your working on scrape paper and just...
Due to COVID lockdowns, there were no exams in April 2020.
This is compound distributions which is now no longer in the syllabus.
Yes, it's ANOVA. So no longer in scope.
You're welcome. I confess I genuinely thought we already had a thread with this in - so sorry it wasn't done sooner.
I'm so pleased - could you share the source to benefit other students? Many thanks John
The linear predictor is just \(\alpha\) for the 1st 10 values of i, \(\beta\) with the next 5 values of i and then \(\gamma\) for the last 20...
Alas, I've only gone back to 2013 as it took ages - but hopefully the topic areas which are now off syllabus should make it quicker to identify...
No worries - you should be able to attach an image to posts if it makes it easier.
I can't see a problem with this. However, as with all calculations, you will need to show your working to get full marks.
It's just using the CDF of the uniform distribution given on page 13 of the Tables. Alternatively, you could just integrate between the start...
1. Yes, it's out of scope. See my thread here: https://www.acted.co.uk/forums/index.php?threads/ct3-questions-that-are-out-of-scope-of-cs1.19125/...
Yes, these are out of scope. I've now created a thread detailing all the old CT3 questions that are out of scope here:...
Questions on PGFs are out of scope: S18 Q2 Questions on compound distributions are out of scope: A13 Q10, S13 Q8iv-, A14 Q7ii-, S14 Q3, A15 Q3,...
1. PGFs are no longer on the syllabus 2. Part (iii) is still on syllabus as it's just a weighted average of the means, but ANOVA in parts (iv)...
Glad I could help.
The p-value is the probability of a more extreme value than your observed statistic (ie the probability of being more in the tail). Hence, the...
Suggest you look at this recent thread on the forum: https://www.acted.co.uk/forums/index.php?threads/pca.19022/
This was very cool. Thanks for sharing.
1) You just divide \(P(X=x)\) by \(P(X=x-1)\) for the Poisson. 2) So we have 87,889 zero's, 11,000 one's, 1,000 two's and so on. So the...
That's exactly correct. If the question doesn't say, we test at the 5% level and you would have received full marks in the exam had you done this....
Because the distribution of \(S^2\) is very skewed. You could quickly test this out using R and simulating lots of samples from a normal...
Given that the exams are now online - it's unlikely that you'd be asked to prove a result that is given in the notes. As you'd then just be...
We're told that U|V ~ U(0,V). So they've just quoted the mean and variance of this distribution. Likewise for V. Either turn back to Chapter 2 and...
You could, but you must still show your working to gain full marks just as you would with a calculator.
CS2 is a huge exam, so I wouldn't recommend taking it with CM2.
The standard error of the estimator of the mean is the standard deviation of the estimator - hence they calculate the standard error of the...
As a general rule of thumb, we add the most significant variables first (ie those with the highest correlation). The adjusted \(R^2\) is a quick...
If you studied maths at Oxbridge and get an MA, then if you go for FIA you can spell MA FIA.
The PACF at lag 1 is the conditional correlation between, say X1 and X2, given all the values in between (ie fixing those values). Since there...
I can confirm that any students who are close to the pass mark are automatically given a third review from one of the chief examiners. The chief...
I know that there's no major changes to CS2 due for 2023 exams. Which CM are you referring to, CM1 or CM2? I'll get one of my colleagues to reply.
No. This assumption is made in the notes - because on paper it's the only way to deal with small samples. In the real world, the assumption of...
In the case where there are only two outcomes, then a contingency table test is actually equivalent to the two sample proportions test. However,...
Yes, the question isn't clear. The examiners wanted the variance of the distribution of X for the various values of theta.
I suppose not. But it has numerous features that make life easier - including autosuggestion, error spotting, bracket checking and so on.
To load a csv file - you could either use: object <- read.csv("<filename>.csv") or use the "import dataset" option in the Environment window in...
I believe, though I could be wrong, that it is more convenient because it depends on past observable values - whereas the MA doesn't have that...
Are you referring to the theoretical distribution of the prior p~beta(2,3)? In which case the mean is 2/(2+3) = 0.4 and the variance is exactly...
They're given in "text format" as they are .R files which can be run in R, rather than PDFs or word documents which can't. Whilst they're fine in...
If we didn't double it then we wouldn't be able to tell whether we'd reject H0 or not unless they told us it was a one or two sided test. As for...
So this "towards the mean" is only used in hypothesis tests in Chapter 10. This is because when we calculate the p-value for the binomial/Poisson...
You can try the assignment yourself. If you wish to have them marked then you can pay for that and they'll send you the latest copies if you have...
Presumably by perfect you mean that it accurately represents the true population. This is unlikely in practice unless the sample is large and...
Some students do manage to pass this way, but the pass rates are much higher for students who attend tutorials and even higher for those who...
Nope, but the question you should be asking is "is it helpful to me passing?" So you should still do it regardless of whether or not you get...
Yes.
It's always worth dropping an email to the examinations team at the IFoA.
I've seen truncating the width of lines (and so just by writing shorter comments fixes it) but this appears to be truncating of the length of the...
Why not mention this problem at the beginning of the exam paper as a note to the marker: "Apologies in advance, but due to (insert reason here,...
Yes - it's a good plan to get everything right in your script window - then execute it all then copy and paste all the console window into Word,...
Part of the copy/paste ban is to prevent students using pre-written solutions or, obviously, copying other people's work. You still have to be...
i) This is covered in Chapter 4 (Joint Distributions) in the notes using MGFs. Set \(Y=\sum X_i\) and find the MGF of Y. ii) Presumably, you mean...
The examiners have made it very clear that working needs to be shown to receive all the marks. For distributions, you should also only use...
There's more exams now the early exams have paper A and paper B. The only clashes are between very earlier exams (eg CS1) and very late exams (eg...
There are 90 videos each ranging from 5-15 minutes. For each of these there are then exercises to practice the techniques (I could optimistically...
Gutted to hear that you were so close. Given that you are a borderline case, your paper would have also been third marked by the chief examiner...
You can - but it's not recommended because of the time it takes to write equations in equation mode.
Think of it as the difference between pre-recorded and live. The advantage of live is that you can ask questions as they come up and get...
Personal view: This is hardly a scandal. It's a standard business approach of using a loss leader or just a cheaper price to get new business...
Option 1 seems sensible.
Yes, but don't include your name - markers aren't supposed to know!
It appears the newest version of RStudio (1.4) makes copying and paste output from the console into Word more difficult. You'll need to use...
What they're referring to is the paper A - and that excludes the use of students attaching a photo of their handwriting. For paper B, we...
You are welcome to address this to the IFoA's examinations team (who are responsible for the exams - rather than ActEd or students on this forum)...
The examiners ONLY give marks for the MCQ answer and none for the working. So writing the working will gain you nothing except lost time, as the...
As a marker for CS1B, I know that there is no template for our subject. Please don't include your name - but do include your ARN.
Nope. Although, there is a general nesting order of brackets: { [ (
SP1 overlaps the syllabus of SP2 so there would be some natural synergy.
Just compare it with the SP2 solutions which are available for free on the Profession's website:...
You're using a normal approximation to the binomial and then doing the subtraction of two normal distributions (see p41 of chapter 4).
