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October 22, 2020, 06:00:51 pm

Author Topic: Study Score Calculator (open beta)  (Read 2300 times)  Share 

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keltingmeith

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Study Score Calculator (open beta)
« on: August 26, 2020, 03:58:16 pm »
+20
After opening the prediction thread to find multiple people asking for full sets of subjects, I snapped and decided to write an excel spreadsheet to calculate things for people because tbh it's a lot less effort lol

How to use the spreadsheet:
Right now, it's set to view permissions so nobody breaks it. At the top, click "File>Make a Copy" to make a copy of it to your own Google account. You can edit the spreadsheet there. Also, some of you might not be used to sheet terminology - when I say "cell", I'm referring to those rectangle-like boxes you can write things into.

From there, everything you need to do is in the first tab - titled "Study Score Calculator"

In the red cells, list your subjects. As you start to write your subject, it should appear on the list - select your subject from that list. You can also just click each arrow on the right of the cell and select your subject from the drop-down list. If your subject isn't there, I haven't added it yet. See below for why

In the green cells, list your subject scores AS PERCENTAGES. If you don't, it won't work. Note that the first column should have graded assessment 1, the second column should have graded assessment 2, and the third should have graded assessment 3. If you don't know what these are, look them up, they'll be listed in the study design of the subject - just open it up, and ctrl+f "graded" and it should pop up. Usually, GA1 is unit 3 SACs, GA2 is unit 4 SACs, and GA3 is the exam - but this is not always the case, particularly for subjects with multiple exams.

Finally, your predicted study score should appear in the blue cells.

I've included some examples on the calculator so you can see how things should be entered.

GA1 for mathematics subjects is slightly different and stupid, so see the second calculator in the yellow cells for how to calculate GA1 for a maths subject


Let it be known - it was taking far too long to do every single subject that VCAA offers, so I decided to just do a few I've seen being asked and left it at that. If there's a subject you want added, post below, and I will add it. But also, it's not hard to do, so feel free to add your own subjects yourself in the tab titled "Subject Grade Distributions 2019". You'll find the data you need in the 2019 grade distributions to fill everything out. The spreadsheet should be able to handle everything from there. (I'm likely still adding subjects as you're reading this topic lol)


How the spreadsheet works:
All of VCE basically operates on a bell curve. No, really, all of it. The reason for this is because of a statistical phenomena called "Central Limit Theorem". It's actually kinda really cool.

If we use the grade distribution data, we can then convert your graded assessments so that we know where you lie on the bell curve. This is called a "z-score"

By multiplying each z-score by their appropriate weightings and adding them together, this tells us where you'd lie on the subject's final z-score.

From there, we just multiply the final z-score by the mean and standard deviation of the raw study score (this is 30 and 7 for all subjects), and this gives you a predicted raw score.

Fun fact: this is almost the exact method VCAA uses to calculate your study scores. The only difference is they re-distribute your score after finding your final z-score, instead of just converting it to the raw score distribution like I do.


Limitations of this spreadsheet:
Nobody has pinpoint prediction accuracy. Even though this calculator will give you an exact score, take it with a grain of salt - expect it to be off by up to 3 points in any direction.

This method particularly has issues at the upper-end. This is because the graded distributions aren't true normal distributions, because they're cut off at 100%. To highlight these, you'll notice the Accounting example actually has 100% listed for every GA - and comes out with a final study score of 43. Ooft.

This method assumes your SAC scores won't change. The good news is, if you're rank 1, and your exam scores are higher than your SACs, your SAC scores likely won't scale down. However, if you're not rank 1, then it depends on how good your school is. If you're in the top 50%, and your school usually averages a raw score of more than 30 in that subject, your score likely won't go down. If you're not in the top 50%, or your school usually averages below 30 - that doesn't mean your SACs will go down, but I can't guarantee they won't go down. Sorry about that.

Like my fifth subject calculations that I recently posted - this spreadsheet uses data from 2019. This will change from year to year, so even if my calculator nails what your 2019 score would've been, if the distribution for your subject changes too much in 2020, then this score will be completely different to what your 2019 score was.


Finally, this spreadsheet is basically only for checking you're on track. Remember it's flawed, and if you're doing particularly well it's likely underestimating your score (for real - if you get 100% in all of your scores, and they don't change, you will get a 50 - not a 43).

(also, people who did VCE last year and have your scores saved somewhere, I'd love to use them to benchmark the spreadsheet to see how accurate/precise it actually is - send me a PM! And if the spreadsheet ends up being particularly bad, I'll make another post in this topic telling you all to stop using it)

Important to note: This spreadsheet is for 2020 use ONLY. The weightings are based on the ones in the 2020 study designs, which were changed because of COVID. Future years will require me to fix that part of the spreadsheet
« Last Edit: August 26, 2020, 06:01:26 pm by keltingmeith »
Try out my study score calculator, request your subjects, and help give feedback if you've already completed VCE!

Dear VCE 3/4 Chemistry students: you do not need to know how to do pH calculations for your exam. That is all.

Bri MT

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Re: Study Score Calculator (open beta)
« Reply #1 on: August 26, 2020, 05:39:25 pm »
+7
If you are not sure what GA1, GA2, GA3 means it's usually as below or best approach is to do as asked and look it up for complete confidence; the study design is your friend here.

For subjects with 1 exam: GA1: u3 sacs, GA2: u4 sacs, GA3: exam
For subjects with 2 exams: GA1: sacs, GA2: exam 1, GA3: exam 2


Stickying this thread, thanks keltingmeith for the great resource!

Edit: has been pointed out that languages don't always obey the guidelines described above. Some do, some don't so check :)
« Last Edit: August 26, 2020, 06:19:00 pm by Bri MT »

keltingmeith

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Re: Study Score Calculator (open beta)
« Reply #2 on: September 12, 2020, 12:06:01 am »
+7
UPDATES:

Firstly, I've added some more subjects as they've been asked in the study score prediction thread, and one that was PMed to me. If you want more subjects, just tell me what you want added - it's much easier on me to add them by demand than it is to do all of them at once.

Secondly, there was a bug in HHD in that it was underpredicting your exam contribution. This has now been fixed - if you predicted a score for HHD before, you should predict again for your own peace of mind.

Thirdly, I didn't like that I was predicting a single score when I don't know how accurate the calculator is. So, I've changed the score calculator such that it now gives you a range of scores based on how far away you are from the mean. This should hopefully address the fact that my calculator is less accurate at the extremes, so the calculator should now be much more solid for higher study score calculations! (though it's still not perfect. High marks just inherently have higher variability, based purely on the way VCAA works their system) For those interested in EXACTLY what variability I'm currently using, I'm predicting 25% variability in the z-scores. This equates to anywhere from 1 point difference in the final score to up to 5 points difference depending on how far you are from the mean, and what subject you're doing.

Finally, I've now added a VET subject, by demand! VET subjects only have two GAs, so I've included a little note in the middle explaining how to input the numbers as a result. I've also included a note about low student numbers, as this marks the first subject added with numbers so low that it means the calculator is even less reliable.
« Last Edit: September 12, 2020, 12:09:10 am by keltingmeith »
Try out my study score calculator, request your subjects, and help give feedback if you've already completed VCE!

Dear VCE 3/4 Chemistry students: you do not need to know how to do pH calculations for your exam. That is all.

homeworkisapotato

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Re: Study Score Calculator (open beta)
« Reply #3 on: September 12, 2020, 11:20:59 am »
0
Hey keltingmeith, thank you so much for doing this! I wanted to find my score for Bio, but I couldn't find it. I was wondering if you took it off or am I just super blind ahaha?
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Re: Study Score Calculator (open beta)
« Reply #4 on: September 12, 2020, 11:30:28 am »
0
Would it be too much to ask for Texts and Traditions (since it's a tiny cohort)?
VCE 2018-2020
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keltingmeith

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Re: Study Score Calculator (open beta)
« Reply #5 on: September 12, 2020, 04:29:14 pm »
+4
Hey keltingmeith, thank you so much for doing this! I wanted to find my score for Bio, but I couldn't find it. I was wondering if you took it off or am I just super blind ahaha?

Bio is definitely still there! Maybe because the subjects were sorted in order I added them, not alphabetical order, you couldn't see it? I've fixed that now :) I've also added Biology to the list of examples for you, so you don't have to search if you copy a fresh sheet, hahah. You can also manually enter the subject name - you don't have to go by the drop-down list. The only problem is if you don't write the subject name EXACTLY as it is in the drop-down list, I can't guarantee you'll get the right results.

Would it be too much to ask for Texts and Traditions (since it's a tiny cohort)?

No cohort is too tiny for me to add - my metric for adding subjects is, "will at least one person look up a score with this subject?". T&T is now in the list - though be warned that because it IS a smaller subject, the calculator is going to be less accurate than it is with your other subjects. Not something I can help, I'm afraid.
Try out my study score calculator, request your subjects, and help give feedback if you've already completed VCE!

Dear VCE 3/4 Chemistry students: you do not need to know how to do pH calculations for your exam. That is all.

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Re: Study Score Calculator (open beta)
« Reply #6 on: September 12, 2020, 04:45:25 pm »
0
Am I blind? I... don't see English? If it's not there could you please add it?

If you could add History: Revolutions that would also be nice :)

Thank you!
VCE 2018-2020
2019: HHD 3/4 (31->?)
2020: Methods 3/4 (36?->?) | Revolutions (France/Russia) 3/4 (32?->?) | English 3/4 (40+?->?) | Texts and Traditions 3/4 (35?->?)
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Re: Study Score Calculator (open beta)
« Reply #7 on: September 12, 2020, 04:49:24 pm »
+1
Whilst you're at it, if you could add food studies as well, that would be great!

Thank you, I also really appreciate how you've made it for 2020 with the adjusted study design as well :)
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keltingmeith

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Re: Study Score Calculator (open beta)
« Reply #8 on: September 12, 2020, 05:15:38 pm »
+5
Am I blind? I... don't see English? If it's not there could you please add it?

If you could add History: Revolutions that would also be nice :)

Thank you!

English was the first thing I added when I decided not to take the "add every subject" approach lol. List is also sorted alphabetically now, so you should be able to find it without much ease? Revs has now been added, too

Whilst you're at it, if you could add food studies as well, that would be great!

Thank you, I also really appreciate how you've made it for 2020 with the adjusted study design as well :)

Thank me after I then have to change it back for the old study designs lmfao, though I guess not a concern for you ;) Food studies is now added



EDIT: I have good news for everyone! Someone was nice enough to send me their results for methods, and the calculator was able to predict their study score within the precision I've set! This doesn't mean the calculator is working perfectly, but it's now proven to work for at least a higher-mid methods score. If anyone else is able to send me their score/results for any subject, please do - more testing will only help me in defining those precision values I've designed (and who knows - maybe this spreadsheet is more precise for some subjects, and I can lower their precision bounds to get more precise scores for people?)

Based on the result I have, I'm predicting within 20% deviation of the z-score. I'm keeping the bounds at 25%, because one test isn't good enough for me to want to change the precision parameter, but still a happy result!
« Last Edit: September 12, 2020, 05:37:30 pm by keltingmeith »
Try out my study score calculator, request your subjects, and help give feedback if you've already completed VCE!

Dear VCE 3/4 Chemistry students: you do not need to know how to do pH calculations for your exam. That is all.

homeworkisapotato

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Re: Study Score Calculator (open beta)
« Reply #9 on: September 12, 2020, 05:36:37 pm »
0
Bio is definitely still there! Maybe because the subjects were sorted in order I added them, not alphabetical order, you couldn't see it? I've fixed that now :) I've also added Biology to the list of examples for you, so you don't have to search if you copy a fresh sheet, hahah. You can also manually enter the subject name - you don't have to go by the drop-down list. The only problem is if you don't write the subject name EXACTLY as it is in the drop-down list, I can't guarantee you'll get the right results.
I'm so bad with technology, thank you so much! You're such a legend!!
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Re: Study Score Calculator (open beta)
« Reply #10 on: September 12, 2020, 05:58:06 pm »
0
Found a bug - playing around with HHD just to see what scores I needed to get the score I got, and found that if I put in 50% for all three the lower was 29 and the upper... 28...? Trying a couple of other subjects including English I found those values gave me a higher lower than upper bound (English it was 29 and 27). Thanks for doing this, but you might want to look into that?
VCE 2018-2020
2019: HHD 3/4 (31->?)
2020: Methods 3/4 (36?->?) | Revolutions (France/Russia) 3/4 (32?->?) | English 3/4 (40+?->?) | Texts and Traditions 3/4 (35?->?)
Aiming 92+ ATAR
Aims for uni/life
-Bachelor of Nursing/Bachelor of Midwifery at Deakin
-Write/publish books (thanks NaNoWriMo.org!)
For Narnia!

keltingmeith

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Re: Study Score Calculator (open beta)
« Reply #11 on: September 12, 2020, 06:02:24 pm »
+5
Found a bug - playing around with HHD just to see what scores I needed to get the score I got, and found that if I put in 50% for all three the lower was 29 and the upper... 28...? Trying a couple of other subjects including English I found those values gave me a higher lower than upper bound (English it was 29 and 27). Thanks for doing this, but you might want to look into that?

Oops - yeah, I know exactly why it's doing that. Should be fixed momentarily, but I'll need to run some quick tests first. Check back in 15 minutes

EDIT: Make that 4 minutes, lol. All fixed.

EDIT 2: I now have the exact scores (as in, what actual percentages they got for each GA) for someone and the study score they got, and my calculator got the result bang on! So we have at least 1 very good calculation from it, lending it quite a bit more weight.
« Last Edit: September 12, 2020, 06:36:55 pm by keltingmeith »
Try out my study score calculator, request your subjects, and help give feedback if you've already completed VCE!

Dear VCE 3/4 Chemistry students: you do not need to know how to do pH calculations for your exam. That is all.

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Re: Study Score Calculator (open beta)
« Reply #12 on: September 15, 2020, 05:27:45 am »
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well guess no one can get above 46 in further then lol unless they get bonus marks for writing a new question and answering it on the exam 😂😂😂

keltingmeith

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Re: Study Score Calculator (open beta)
« Reply #13 on: September 15, 2020, 09:48:42 am »
+2
well guess no one can get above 46 in further then lol unless they get bonus marks for writing a new question and answering it on the exam

Yeah - known problem with the calculator, I predicted it before I even released it :P

The reason is because at the top end of the result curve, all the results bunch up and so it's hard to differentiate each student. The good news is this effect goes down REMARKABLY as you move away from 100%. For example, my calculator predicts that the difference between 100% and 95% is only 2 scores - most people would it expect it to be way more (for context, they say at 50 for further, 1 mark lost = 1 score dropped. 5% is 4 marks in exam 1, and 6 in exam 2). Then the difference between 90% and 95% is only 1.5 scores - which, again, it should be way more.

I think that the 90% scores aren't too much off the mark as a result, but yeah anything above that is DEFINITELY being underpredicted, especially for subjects like Further with more students clumped up around the top (i.e., smaller convergence to a bell curve).

I do wish I could fix this, or at least tell you how much the calculator is likely underpredicting you, but I can't do that without student's scores to test with, sorry :(
« Last Edit: September 15, 2020, 11:05:55 am by keltingmeith »
Try out my study score calculator, request your subjects, and help give feedback if you've already completed VCE!

Dear VCE 3/4 Chemistry students: you do not need to know how to do pH calculations for your exam. That is all.

onlytherealonesknow

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Re: Study Score Calculator (open beta)
« Reply #14 on: September 16, 2020, 07:13:08 am »
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Yeah - known problem with the calculator, I predicted it before I even released it :P

The reason is because at the top end of the result curve, all the results bunch up and so it's hard to differentiate each student. The good news is this effect goes down REMARKABLY as you move away from 100%. For example, my calculator predicts that the difference between 100% and 95% is only 2 scores - most people would it expect it to be way more (for context, they say at 50 for further, 1 mark lost = 1 score dropped. 5% is 4 marks in exam 1, and 6 in exam 2). Then the difference between 90% and 95% is only 1.5 scores - which, again, it should be way more.

I think that the 90% scores aren't too much off the mark as a result, but yeah anything above that is DEFINITELY being underpredicted, especially for subjects like Further with more students clumped up around the top (i.e., smaller convergence to a bell curve).

I do wish I could fix this, or at least tell you how much the calculator is likely underpredicting you, but I can't do that without student's scores to test with, sorry :(

All good just thought it was funny. :)