Chris Graham

Chris Graham on Calculate the areas of polygons 8 years, 5 months ago

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Chris Graham commented on Calculate the areas of polygons 8 years, 5 months ago

Nice question. However, "a trapezium can be interpreted as half of a parallelogram, this is shown below", isn't really shown below. Since you have included the graphic of the parallelogram, I think that you need to be consistent, and include something along the lines of this: http://www.mathguide.com/lessons/pic-demotrapezoid.gif

Chris Graham on Calculating a simple rate of pay 8 years, 5 months ago

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Chris Graham commented on Calculating a simple rate of pay 8 years, 5 months ago

Since it's a straightforward question, it might be a nice one to incorporate Christian's random person extension: see https://numbas.mathcentre.ac.uk/question/23094/the-random-person-extension/ 

Chris Graham on Creating Frequency Tables 8 years, 5 months ago

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Chris Graham commented on Creating Frequency Tables 8 years, 5 months ago

I would suggest moving the current statement to the top of the advice and then move everything before "Complete the frequency table" into the statement. Perhaps the scores could go into a table. 

Chris Graham on Which coin is more likely to be biased? 8 years, 5 months ago

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Chris Graham commented on Which coin is more likely to be biased? 8 years, 5 months ago

I do like this question, however as it stands the marking is unsatisfactory. If there are no marks for b) then it is very hard to justify the mark for c), since it depends directly on the student's interpretation. I would prefer Christian's suggestion below of careful wording and keep the mark in part b). You need the same careful wording in c) too. 

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

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

I'm not keen on d). It depends on your definition of getting closer - it is staying at the same value whilst the experimental is moving towards it. That's closer in my book. I think I would lose this part altogether, as I'm not sure it adds any value.

In b), I don't think that you need the bullet points under "In this case you have..." if you are later summarising the outcomes in table 2.

You advice in c) ends up being very confusing. The distribution of outcomes in the table are way off the expected, given the probabilities in table 3. I was told that the experimental probability of rolling a 3 is 0.09 and is very close to the theoretical, but it is not, it's way off.

RE your question below, yes, displaying the simplified fraction would be better.