Chris Graham

Chris Graham on Decimals to fractions 8 years, 5 months ago

Gave some feedback: Has some problems

Chris Graham commented on Match statement to graphs 8 years, 5 months ago

Hmm, might need Christian's help with this one; something to do with the timing of the variable replacements I would guess. However, could the 'numbering' not be placed outside of the SVGs here? So that they are static, whilst the images are shuffled?

Chris Graham commented on Decimals to fractions 8 years, 5 months ago

Hi Lauren, I guess this was after we sorted the other bits on Friday. It appears as though this could be due to floating point precision, such that f2 is not considered a precise integer for the purpose of obtaining the gcd. I have added precround(...,0) to the definition of f2 and I think that this has solved it.

Chris Graham commented on Theoretical Probability vs Experimental Probability 8 years, 5 months ago

As discussed, would be better as two questions with separate parts. In part (b) the student will answer the second two gaps based on their interpretation of the coin's bias, and offering feedback after the first bit would then set them down the right track.

The drop down question should work with the opposing terms either way round. This would require a marking matrix (it would need to be its own part, but I've suggested you do that anyway), or this could be replaced with multiple choice statements.

I don't think "Is this coin biased?" is a fair question here: statistically it may or may not be, so as suggested you could replace this with two experiments, with a distractor set of results for small N, and then ask the student which coin is more likely to be biased. This is assessing their understanding that the experimental approaches the theoretical probability.

Chris Graham commented on Decimals to fractions 8 years, 5 months ago

Hi Lauren, you currently have amissing answer(s) for your gaps. If you can sort that and I'll also come and see you.

Chris Graham commented on Basic Probability Questions 8 years, 5 months ago

As discussed, it would be nice to have an example in the statement.

Chris Graham on Solving linear inequalities 8 years, 5 months ago

Gave some feedback: Has some problems

Chris Graham commented on Solving linear inequalities 8 years, 5 months ago

You should pull $x<$ outside of the gap (or $x>$, as appropriate) and adjust the correct answers accordingly. The way the marking works is that the part's correct answer is evaluated at a number of test points, and in this case will return logical values: let's say it evaluates to true at all of the test points. If that's the case then any student answer that also evaluates to true at the test points will be marked as correct. Have a go yourself in part (a) with, say, x<100 or x=x.

Some of the wording in the advice needs to be carefully considered. For example, in part (a), are you really "subtracting the constant"? And there is a "constant" on both sides (thoug I appreciate that you give the value). I think I would be more direct and offer motivation for the step, with something like "to obtain x on its own on the left hand side, first add 8 to both sides"

There are a few typos in the advice, which is otherwise laid out nicely.

Chris Graham on Surds simplification 8 years, 5 months ago

Gave some feedback: Has some problems

Chris Graham commented on Surds simplification 8 years, 5 months ago

Where you are using \sqrt, you should have braces around the argument \sqrt{...}. Note the difference: $\sqrt100$ and $\sqrt{100}$. 

Also the nth root can be written \sqrt[n]{...}, e.g. \sqrt[3]{100}, $\sqrt[3]{100}$.

If this is the first question on surds when we put questions together, then I think an example surd would be beneficial in the statement.