2010 PSLE Discussion
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Err… it Peirce.
Though not banded, some parents and teachers of DS school have good comment about the school. It may be an up and coming school. -
Hi JonC,
Thanks a lot for the reassurance…tink I will tell my friend to put as 1st choice then…but chances may be low, coz their COP is betw 206-208…so 203, really quite slim chance…
What about Serangoon Garden Sec(it’s the nearest, so very tempting!!),
Guang Yang, CHong Boon & Yio Chu Kang?? Anyone has valuable advice/comments?? Thanks in advance!! -
atutor2001:
I am making informed guesses of the PSLE total raw-scores from the extreme cases. The estimate is for overall mean and SD. [b]Since the papers are easy, the SD should be quite consistent for all 4 papers[/b].
I am using PSLE score here to estimate - not raw score from schools.verykiasu2010:
every school's raw score is of no help in the estimate because their standards are different from school to school. A child from school A with raw score of 380 cannot be compared with another child of the same raw score from school B.
[quote]And nobody actually know the raw scores in the actual PSLE exam, but it is a known fact that every subject's mean and SD are different
[quote]it will be more instructive if the schools provide its own t-score for every student every year and bench mark it to actual performance at PSLE and see where they stand. that will be much more able to predict the PSLE actual scores [/quote]
I know a NYP girl who failed her P6 math in every semester but got an A in PSLE, which explains why the mean for NYP math is ONLY 65.8. She was so demoralised and her parents were so upset. I really cannot understand how such mis-match between prelim and psle standard is of help. So the parents will tell the kid, \"Don't worry, it is ok to fail now. Based on the bench mark to actual performace at PSLE, you will get A\"
Therefore, knowing that the overall mean is around 69 and yet that school's mean for math is 65.8, we can tell the school that they are doing a disservice to the weaker students. Losing confidence and developing dislike for math is not something that can be corrected easily.[/quote]
you know the actual raw scores for the PSLE ? don't joke / mislead people lah
the papers were easy, BUT not all 4 subjects are all equally easy. what a joke to say there should be \"consistent\" since \"they are easy\". Consistent in what ? consistently different from each and every subject is more like it
why upset ? it just shows that that girl need some waking up to before the PSLE to achiever her potential
the school's overall result is proof that what they do is on the right track : more than 82% scored at least 4As or higher
in every school there are stories of pupil who scored badly in school tests and did well for the PSLE - waking up not too late from the slumber; there are also some proud peacock who did worse in PSLE than in prelim
parents should bear in mind that every subject's mean and SD is different from year to year -
verykiasu2010:
No, I don't professed to know the PSLE raw score. But just to explain how an \"informed\" estimate can be made :
you know the actual raw scores for the PSLE ? don't joke / mislead people lah
.....
(1) Top scorer 282 and 2nd is 279. The difference in the raw score is about (282-279)x4/3 = 4 marks. So it is a fair guess that the top student gets nearly perfect score i.e. 99 per subject (average)
(2) There is a known case of 263 with 4A* (the lowest known T-score in this forum for 4A*). Assuming that this is a case of getting exactly 91 for the A*, I worked out my first estimate of average mean = 64 and SD = 17
(3) Then a new case 3A* + 1A getting only 249 which would not tally with the earlier computed mean and SD. Re-estimated the 263 case to be with average of 92 marks and got new mean = 69 and SD = 15.
(4) Checks were made with other results and so far the estimate is fine.
Then there is this nagging question of how the differing SDs and means for different subjects will affect the accuracy whereby I am computing using information on the combined total and average.
T-score : T = 50 + 10/SD x (Raw - Mean)
If the SD ranges from 14 to 17, the factor 10/SD will range from 0.7 to 0.6 and the change is not great. Since the papers were easy and for the purpose of estimation, I assumed the SD to be constant. (cannot use NY's SD range because their math's SD is unusually high, 17+ as it is well known that their math paper is difficult)
Working with the T-score formula :
Total T-score = T1 + T2 + 73 + t4
Total T-score = 50x4 + 10/SD x [(R1+R2+R3+R4) - (M1 + M2 + M3 + M4)]
Average T-score = 50 + 10/SD x [(R1+R2+R3+R4)/4 - (M1 + M2 + M3 + M4)/4]
Note that :
(R1+R2+R3+R4)/4 = Average Raw Score
(M1 + M2 + M3 + M4)/4 = Average Mean
So Average T-score = 50 + 10/SD x (Average Raw score - Average Mean)
Therefore, through \"informed\" guess of the Total Raw Score ie. using cases of highest T-score and lowest T-scores for certain combination of grades, I can estimate the Average Raw Score and then work out the estimated Average Mean and \"assumed\" SD.
Hope this explanation will give a better idea of how the estimates are done. No intention to mislead anybody.
My next self-question is \"What is the use of such estimation?\"
It has been bugging me since my kids' time as to what is the \"mean\" in the actual PSLE. Through this estimation, I am now clearer that for \"normal\" PSLE papers, the mean is around 70. That means, a child must achieve an average of 70 marks to \"pass\" for Sec Express. I can also re-distribute the average mean to different subjects based on \"experience\" example, Math will be more than 70 about 75, Science will be about 65....)
Then how is this useful, as papers changed over the years. To me, as long as the paper is normal, the mean will be around 70 and the SD around 15. If the paper is difficult, the mean will go below 70 and the SD up to 18 (as show in NY's info for math paper)
Sad that you take these estimates as misleading. Please just ignore them. For others who find them so, please also ignore my postings. Will make myself scare in future. -
atutor2001, hey
don’t make yourself scarce. good defence
my guess is that the mean and SD is much more complex
from a student’s perspective, I will never know how many careless mistakes are made in the actual PSLE — I would always think I achieved a certain raw score…and thought I deserved higher t-score; and with the changing emphasis of the exam papers in science and languages, it is even harder to estimate the mean and SD
appreciate your labour to explain your thoughts behind it -
verykiasu2010:
Sad that you view this as a \"defence\" and not an explanation.atutor2001, hey
don't make yourself scarce. good defence
my guess is that the mean and SD is much more complex
from a student's perspective, I will never know how many careless mistakes are made in the actual PSLE --- I would always think I achieved a certain raw score......and thought I deserved higher t-score; and with the changing emphasis of the exam papers in science and languages, it is even harder to estimate the mean and SD
appreciate your labour to explain your thoughts behind it
Anyway, there is nothing complex about mean and SD.
Mean is the average raw score.
SD is the average of \"all the differences of each raw score from the mean\". To take care of \"negative' difference i.e. raw-score less than the mean, we square all the differences first, sum them, average them and finally square root it to get the SD.
The SD reflects the distribution of the intelligence level of the students for the paper. If the paper is very difficult, the SD will be bigger as there will be more extreme cases of \"very good\" and \"very bad\" marks. If the paper is easy, most students will bunched around the mean thus making the SD smaller. -
atutor2001:
complex - NOT in terms of mathematical formula
Sad that you view this as a \"defence\" and not an explanation.verykiasu2010:
atutor2001, hey
don't make yourself scarce. good defence
my guess is that the mean and SD is much more complex
from a student's perspective, I will never know how many careless mistakes are made in the actual PSLE --- I would always think I achieved a certain raw score......and thought I deserved higher t-score; and with the changing emphasis of the exam papers in science and languages, it is even harder to estimate the mean and SD
appreciate your labour to explain your thoughts behind it
Anyway, there is nothing complex about mean and SD.
Mean is the average raw score.
SD is the average of \"all the differences of each raw score from the mean\". To take care of \"negative' difference i.e. raw-score less than the mean, we square all the differences first, sum them, average them and finally square root it to get the SD.
The SD reflects the distribution of the intelligence level of the students for the paper. If the paper is very difficult, the SD will be bigger as there will be more extreme cases of \"very good\" and \"very bad\" marks. If the paper is easy, most students will bunched around the mean thus making the SD smaller.
complex - as it is influenced by human factors, not all students / teachers / markers are 100% predictable as a robot -
atutor2001:
Sad that you take these estimates as misleading. Please just ignore them. For others who find them so, please also ignore my postings. Will make myself scare in future.
Dont atutor.
They are some of us who find your analysis interesting.
sure they are guesstimates- but given the absense of hard concrete data, it s the next best thing. gives us parents some picture. It is not a high resolution pic but atleast a sketch
Initially, the beginning of this year, I too did not know what you were talking about - how can you say , assume etc... :roll:
But after reading some of your posts, playing around with tscore and checking out trends past yrs, etc i understood your conclusions better.
IMHO- a variety of people make the forum interesting, and ur POV adds to this forum.
:celebrate: -
verykiasu2010:
Ha, I finally understand your misgiving. Yes, human factors are difficult to quantify. That is why statistical data is collected, as these are results influenced by human factors. Hence, results of statistical trends and analysis is a reflection of how human factors will affect the results
complex - NOT in terms of mathematical formula
complex - as it is influenced by human factors, not all students / teachers / markers are 100% predictable as a robot
In short, statistics is a measurable means for \"human factors\". The trend will change drastically only when there is a major change that affect the situation that affect the human race e.g. there was shortage of food during PSLE period. Otherwise, the same trend will be expected to repeat year after year. -
Sun_2010:
Hi Sun_2010
IMHO- a variety of people make the forum interesting, and ur POV adds to this forum.
Glad that you find my POV interesting. Anyway, whenever my DH sees me in this forum, his usual comment is :
\"You too free ah? Better let others think you are a fool and keep your mouth shut then open it and removed all doubts.\"
If he sees my exchanges, his 2 front teeth will drop off. Guess it's time to take his advice seriously.
All the best for your kids' education.
Regards
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