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#### Checkpoint description

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#### Christian Lawson-Perfect3 years ago

Gave some feedback: Should not be used

#### Christian Lawson-Perfect3 years ago

Saved a checkpoint:

The options don't explicitly list two events! They're all of the form "event A given event B" - B isn't an event you can put a probability on, because it's already happened.

I can't find a quick way of rewording this so it makes sense, so I'm marking as shouldn't use.

Published this.

#### Elliott Fletcher3 years ago

Thanks for the feedback Chris, i have tried a new way of formatting the advice for part b), so hopefully it looks better now. Also i have tried to draw my conclusions earlier in b) as well, i just left it as it was for the die one as i thought there wasn't much more i could do for that one.

#### Elliott Fletcher3 years ago

Gave some feedback: Needs to be tested

#### Chris Graham3 years ago

Gave some feedback: Has some problems

#### Chris Graham3 years ago

This looks good now. Just a couple of small changes to the advice:

• It doesn't make sense to number the parts of the advice in b), since they are not numbered in the question. Either number them (i),(ii),(iii), or find a different way to format the advice for b).
• The student does not need to work out the probabilities in order to answer the question, which is assessing their understanding of the concept. I would prefer that you draw your conclusion earlier in the advice for each part (e.g. for the cards, at the point where you state there are now only 51 cards in the deck, and only 3 kings) And then go on after that, with something like. "In fact, we can calculate...".

#### Elliott Fletcher3 years, 1 month ago

Thanks for the feedback Chris, i've reworded the statements a bit hopefully they will be clearer now.

#### Elliott Fletcher3 years, 1 month ago

Gave some feedback: Needs to be tested

#### Chris Graham3 years, 1 month ago

I'm not sure there's any reason to have "Must the fraction be reduced" ticked. I can't think of a reason why the student might enter any other equivalent fraction. I would untick to remove the prompt, which could unnecessarily confuse a student.

The following statement,

"Randomly selecting a boy from a class of 15 boys and 15 girls given that the previous randomly selected student from the class was a girl"

is ambiguous and needs to be worded differently. Has the girl been removed from the class? Without that information, it is impossible to answer.

To some extent, the same is true of the card deck question, which could also be clearer.

#### Chris Graham3 years, 1 month ago

Gave some feedback: Has some problems

#### Elliott Fletcher3 years, 1 month ago

Gave some feedback: Needs to be tested

#### Elliott Fletcher3 years, 1 month ago

Created this.
Identify independent events Should not be used Elliott Fletcher 20/11/2019 14:40
The gambler's fallacy - probability of getting heads again after repeatedly getting heads Ready to use Christian Lawson-Perfect 20/11/2019 14:43
Maria's copy of The gambler's fallacy - probability of getting heads again after repeatedly getting heads draft Maria Aneiros 27/05/2019 02:29
The gambler's fallacy - probability of getting heads again after repeatedly getting heads draft Xiaodan Leng 11/07/2019 02:00
The gambler's fallacy - probability of getting heads again after repeatedly getting heads draft Patricia Cogan 16/01/2020 10:46

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