April 2019 Paper 1

[rlsrachaellouisesmith]

Hi

I have just completed Paper 1 April 2019 and I accumulated a few questions:

1) When watching the online classroom it states that in the Audit trail we should include our spreadsheet conventions and parameters however these were not included in the model solution Would you recommend including them?

2) In the model solution student A19 is mentioned as having a zero score, did we have to mention this?

3) When is it appropriate to use STDEV.P and STDEV.S? I used STDEV.S when calculating the standard deviations for the school scores, but in the model solution STDEV has been used, should I always use STDEV?

4) I completed my additional calculations in the clean data tab, whereas in the model solution an Analysis tab has been used. Would I get marked down for completing calculations in the clean data tab?

5) Would I have lost marks for putting the T-test tab before the results and charts tab and explaining it in my audit trail before the results and charts?

6) Would I have lost marks for including the sensitivity calculation on my results and charts tab rather than including a separate Sensitivity tab?

7) The graph was also included on the sensitivity tab but we were not asked to produce a graph, would I have lost marks for not producing this?

8) When calculating s1 and s2 for the pooled variance Var.S was used, would it have been ok to use STDEV.S instead and square this?

9) I find it difficult to determine what exactly to write in the Objective/Purpose section. It looks like you can just rephrase the background information and then list the various items we have been asked to calculate. Would you suggest this is an acceptable approach, or do you have any other guidance?

Thank you

Rachael

 

[Sarah Byrne]

You should document everything in your spreadsheet, so yes, briefly explain what parameters are included (no need to give values). Worth including spreadsheet formatting to help the user, but it won't explicitly earn you marks.

You should explain any data issues and changes in the audit trail. This specific point probably scored marks under the reasonableness checks in the marking schedule.

The .S suffix functions should be used if the data represents a sample, and .P if the data represents the population. But it will only make a small difference to the end result for a reasonably sized data set as .S uses n-1 and .P uses n. Just avoid mixing them for the same data.

You can complete calculations wherever you want. If the spreadsheet structure could be improved, you might a mark or two under the 'good spreadsheet practice' part of the question. The same goes for doing calculations in a non-logical order. As long as your spreadsheet flows (left to right) you are fine. I wouldn't expect your solution to be identical to the examiners, this doesn't mean it is incorrect

If no graph is asked for it won't be on the marking schedule. However, it may have been included as a reasonableness check, but you could have done an alternative check to earn the mark.

You could use STDEV and square it, but if you can use a simpler function that is easier to explain I would do that.

Aim the audit trail at another student who is picking up the work when you are out of the office. The introduction needs to give enough information that they know this is the right spreadsheet for the piece of work they are being asked to do. So, a brief bit of background about the client and the purpose of the work, then say what the spreadsheet calculates.

Sarah

 

[rlsrachaellouisesmith]

Hi Sarah
A couple of follow up questions on this one.

1) In the mark scheme there are 5 marks for reasonableness checks in the spreadsheet part of the mark scheme. This means we either need to write our reasonableness checks in the excel workbook or include automated reasonableness checks there, is that correct? Or is it sufficient to include the reasonableness checks only in the written audit trail, would these 5 marks still be obtained if they are not written in the spreadsheet?

2) The chart for profit from 100 simulations has no x axis which is not something we are ever advised to do. I used rank for the x axis but could we also use simulation number?

Thank you,

Rachael

 

[Sarah Byrne]

1. Reasonableness checks can just be included in the audit trail as comments about why the results appear as would be expected. The mark scheme for these has now changed and they score under the audit trail which makes more sense. You could include these as automated checks in the spreadsheet, which is fine. These would need to be documented in the audit trail and the results explained. You'll still earn the marks if they are just comments in the audit trail though.

2. I think here it is OK not to have an axis as the simulation number doesn't really tell us anything particularly useful. You should label the axis 'simulations' or similar, but this is one of a very small number of cases where I think this is fine. You could have labelled it more clearly (as you suggested) and that would have been fine too!