Transition to university

Elliott Fletcher on Probability - Notation and Conversion between Percentages, Decimals and Fractions 8 years, 5 months ago

Gave some feedback: Needs to be tested

Christian Lawson-Perfect on Compute the partial sum of an arithmetic sequence 8 years, 5 months ago

Gave some feedback: Has some problems

Christian Lawson-Perfect on Compute the partial sum of an arithmetic sequence 8 years, 5 months ago

Saved a checkpoint:

Fixed a few typos...

You need to show the limits of the sum: $\sum_{i=1}^n$ instead of just $\sum$.

There are a couple of steps you need to carry out in order to work out the partial sum given a list of the elements:

• Identify $a_1$ and $a_n$.
• Calculate $n$.

These could be in Steps, to guide students through the calculation.

Similarly in part b), you need to identify the first term and common difference; these could be Steps.

You've put i) and ii) in the advice, but not in the question itself! And they're basically the same question, aren't they?

The advice uses $d$ for the common difference, but never introduces it. And if your first term is $a_0$ instead of $a_1$, the formula for $a_n$ is a lot nicer.

I don't like "We need to find the difference between $20 \rightarrow 30 \rightarrow 40$". That's not a sentence! I'd prefer something like "We need to find $d$, the common difference between consecutive terms in the sequence."

This could be split into two separate questions.

Christian Lawson-Perfect on Limits of accuracy in measuring weight in a gym scenario 8 years, 5 months ago

Gave some feedback: Ready to use

Christian Lawson-Perfect on Limits of accuracy in measuring weight in a gym scenario 8 years, 5 months ago

Saved a checkpoint:

Looks good!

Christian Lawson-Perfect commented on Working with standard index form 8 years, 5 months ago

We could split each part into its own question.

Christian Lawson-Perfect on Working with standard index form 8 years, 5 months ago

Gave some feedback: Ready to use

Christian Lawson-Perfect on Working with standard index form 8 years, 5 months ago

Saved a checkpoint:

Looks good!

Christian Lawson-Perfect on Rounding numbers to a given number of significant figures 8 years, 5 months ago

Gave some feedback: Ready to use

Christian Lawson-Perfect on Rounding numbers to a given number of significant figures 8 years, 5 months ago

Saved a checkpoint:

This is a good question. I like how the second number in part a alwyas forces you to round up to the next hundred.

It might be worth splitting each part off into its own question.

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.

Stanislav Duris on Estimate the mean and find the modal class for grouped data 8 years, 6 months ago

Gave some feedback: Needs to be tested

Bradley Bush commented on Lowest common multiples: train timetable example 8 years, 6 months ago

Good concise question, just a few notes:

• Could the statement be a more formal definition of a multiple followed by what you've already written as a way of thinking of it?
• The first part was really straight forward although it made me feel guilty for not instantly remembering my $16$ times tables.
• For the second part, I think that you need to either make it clear that a train needs to be present on exactly the same minute to clash or maybe think of a different example so that using multiples makes more sense. I.E. if the trains were stopping 1 minute apart, surely they would clash too?
• Maybe you could phrase the question in an alternate reailty where there has yet to be a storm and both tracks are working then just ask for the time when there is a train on both tracks? I'm struggling to be very imaginative here.
• In the advice, it might be good to hint to the fact you are caling lowest common multiples LCM before you start using it by in the first instance of saying lowest common multiples just putting lowest common multiples (LCM) for reference?

Other than that, great question, I learned some times tables :)

Lauren Richards on Find bounds for distance and time spent running, given imprecise measurements 8 years, 6 months ago

Gave some feedback: Has some problems

Lauren Richards commented on Find bounds for distance and time spent running, given imprecise measurements 8 years, 6 months ago

• I can't help but giggle a bit at the phrase "passionate jogger" as it is conjuring up images of a strange running style like Phoebe's from Friends who is definitely a "passionate jogger" haha. I think "keen runner" might be a little better. 
• Part a) states Josh is off for a morning walk but the statement said he ran not walked! 
• "Calculate upper and lower bounds to find an interval for all possible values of the distance run (????d), rounding to 2 decimal places:" should be in my opinion:
• "Calculate the upper and lower bounds of the distance (d) ran by Josh, rounding your answer to 2 decimal places." 
• ADVICE
• You talk about the degree of accuracy but haven't stated what this is. 
• I think the table in the advice is perhaps not in the best place. I think it is a little confusing too so I would perhaps just drop it altogether.
• I think you could condense the information about the distance and speed and the upper and lower bounds. You could just say: 
  "Speed = 9km/h. 
  Upper bound = 9+0.5 = 9.5km/h.
  Lower bound = 9-0.5 = 8.5km/h" and then do the same for time. Then i think is the best time to mention that distance = speed x time. 
• You might want to mention why you are converting time into hours instead of minutes. You also are missing full stops so might want to add those in. 
• In the advice, I don't think lb and ub for Lower and Upper bound is very clear. 
• For part a), you also might want to mention what the lower and upper bound is in WORDS, eg. the lower bound for distance is the slowest speed multiplied by the shortest time. My brain personally would understand that illustration better than LB of speed x LB of time. 
• State that you have rounded your answers to two decimal places in the advice. 
• Same feedback for part b).
• Think there might be a glitch in the last statement of the advice. We were supposed to establish whether Josh ran in under 60 minutes but it said: "Therefore, we cannot confidently say his time was less than 2 minutes as the upper bound for time (67.06min) is above this threshold.".
• I really like this question, it tests lots of skills and has a good context! 

Bradley Bush on Straight line equation application: measuring sunflower height 8 years, 6 months ago

Gave some feedback: Needs to be tested

Elliott Fletcher on Theoretical Probability vs Experimental Probability 8 years, 6 months ago

Gave some feedback: Needs to be tested

Lauren Richards on Finding the $n^{\text{th}}$ Term of a Quadratic Sequence 8 years, 6 months ago

Gave some feedback: Has some problems

Lauren Richards commented on Finding the $n^{\text{th}}$ Term of a Quadratic Sequence 8 years, 6 months ago

• So after you have found the difference between the sequential terms, and then found the difference between the differences, which you found in the question I did to be 8, it is not clear how you would decide to start the nth term off as 8/2n^2. I think you need to add in a line explaining your reasoning for this.
• I don't think the first sentence reads very well. Maybe something more like "We first need to calculate the differences between the terms in the sequence.". and then for the second bit of writing "We can then calculate the differences of the term differences." I totally get that that is quite hard to word without being confusing. 
• I think "original sequence" should probably be capitalised. 
• In the advice, the second bit of writing that finishes with the word differences, is missing a full stop. You're also missing a comma at the end of "difference" near the end of the advice but I think this sentence should be re-worded anyway as it starts with "If", but then doesn't really end it like you would expect. I think it should be something like "We should first find the common difference.".
• No fault of yours but it gets a little confusing with the amount of differences being mentioned, and I think when you refer to the "sequence of differences" you should have sequence of differences in brackets when you first make it to make it clear when you next refer to it. 
• I think differences sequence should be capitalised.
• At the end, you're calculating the difference between 2n and the sequence of differences but you haven't done that in the same way as you have done earlier in the question advice and I think you probably should do. 
• One time I did the question, it said "Then we can find the difference between 1n and our sequence of differences" so I think you should make sure it just states "n" in this case. 
• I think this is a good question, and tricky to make clear! 

Bradley Bush on Straight line equation application: measuring sunflower height 8 years, 6 months ago

Gave some feedback: Has some problems