All About T-Score

[CrazyDad]

justsay:

[quote]So now you have to use Skewed Gaussian, but by how much.

Hi crazydad , can you help this suaku parent to put it in more layman's term. :oops:

Do you mean first T score formula shall apply using their raw score, then Skewed Gaussian will apply to moderate the T score further if the whole cohort don't do well, the Skewed Gaussian is used to push up the marks of the whole cohort ?

Thank you.[/quote]Layman Term as followed;

For example, base on CL raw score in 2007, 2% of students has less than 50 mark and 81% of student has more than 75 mark.

if the cohort has 50,000 student, then 1000 student failed and 40,000 student score 75 mark or more. So average point should be close to 80 point right?
And everybody score are around 80, says from 75 to 90 mark. so the spread will be very narrow.

[CrazyDad]

P6boy-dad:

justsay:

[quote]So now you have to use Skewed Gaussian, but by how much.

Hi crazydad , can you help this suaku parent to put it in more layman's term. :oops:

Do you mean first T score formula shall apply using their raw score, then Skewed Gaussian will apply to moderate the T score further if the whole cohort don't do well, the Skewed Gaussian is used to push up the marks of the whole cohort ?

Thank you.

Statistically, the mean score and the standard deviation are already a moderating tools. What i can say about the T-Score for Chinese (with 80% scoring A and A*) is that, the mean score is VERY high at least 82 and the SD is about 7-8 marks. It means that your child has to score above 82 before he can obtain a T-score of 50 and above. Any marks below the mean score would result in score below 50 for Chinese. I am sure alot of parents dont realise that, thinking that as long as my child score 75 marks would be sufficient. That was why a student who scored 3A* and 1A (chinese) would get a score of 244. The A for Chinese would have given him a T-score of 41 if he scores only 75 marks.[/quote]totally agree

[justsay]

CrazyDad:

justsay:

[quote]So now you have to use Skewed Gaussian, but by how much.

Hi crazydad , can you help this suaku parent to put it in more layman's term. :oops:

Do you mean first T score formula shall apply using their raw score, then Skewed Gaussian will apply to moderate the T score further if the whole cohort don't do well, the Skewed Gaussian is used to push up the marks of the whole cohort ?

Thank you.

Layman Term as followed;

For example, base on CL raw score in 2007, 2% of students has less than 50 mark and 81% of student has more than 75 mark.

if the cohort has 50,000 student, then 1000 student failed and 40,000 student score 75 mark or more. So average point should be close to 80 point right?
And everybody score are around 80, says from 75 to 90 mark. so the spread will be very narrow.[/quote]Thanks for the explanation. What I actually want to know more is the Skewed Gaussian. Thanks.... :celebrate:

[CrazyDad]

Vikaesh:

CrazyDad:

Hi All,

Base on the feedback from all parents and using the result from 2007. 2007 PSLE is pretty similar to 2009; very difficult math, easy Chinese and some tricky Science questions.

I have estimated the parameter to calculate the T score as followed;
CL: Mean = 78, StdDev = 10
EL: Mean = 73, StdDev = 11
Math : Mean = 63, StdDev = 9
Sci : Mean = 67, StdDev = 12

Use the formula : 50 - 10 * (your score - Mean)/StdDev
for each subject. Sum them up, you should get a glimps.

How close will our PSLE results be to the score we get using yr estimations [e.g. plus OR minus 3]





:xedfingers:

:roll: Only time can tell, there are too many unknowns;
1. the actual scores are unknown
2. the parameters estimated base on even more unknown

get the picture?

[CrazyDad]

justsay:

CrazyDad:

[quote=\"justsay\"]

Hi crazydad , can you help this suaku parent to put it in more layman's term. :oops:

Do you mean first T score formula shall apply using their raw score, then Skewed Gaussian will apply to moderate the T score further if the whole cohort don't do well, the Skewed Gaussian is used to push up the marks of the whole cohort ?

Thank you.

Layman Term as followed;

For example, base on CL raw score in 2007, 2% of students has less than 50 mark and 81% of student has more than 75 mark.

if the cohort has 50,000 student, then 1000 student failed and 40,000 student score 75 mark or more. So average point should be close to 80 point right?
And everybody score are around 80, says from 75 to 90 mark. so the spread will be very narrow.

Thanks for the explanation. What I actually want to know more is the Skewed Gaussian. Thanks.... :celebrate:[/quote] Long story...

can check out Wikipedia for the glory details though...

[CrazyDad]

CrazyDad:

justsay:

[quote=\"CrazyDad\"]
Layman Term as followed;

For example, base on CL raw score in 2007, 2% of students has less than 50 mark and 81% of student has more than 75 mark.

if the cohort has 50,000 student, then 1000 student failed and 40,000 student score 75 mark or more. So average point should be close to 80 point right?
And everybody score are around 80, says from 75 to 90 mark. so the spread will be very narrow.

Thanks for the explanation. What I actually want to know more is the Skewed Gaussian. Thanks.... :celebrate:

Long story...

can check out Wikipedia for the glory details though...[/quote]Please go to Wikipedia and search for \"skewed normal distribution\"
:lol:

[Dharma]

atutor2001:

\"How a single subject can change the assessment order of PSLE students\"

OR

\"T-score is not a fair indication of the Students overall performance.

Hi atutor2001,

Frankly, if you ask me the subject that affects the T-score of the pupils most is MT. With such high % of pupils scoring A and A* in MT ranging from 75% to 82%, the average score is likely to be very high probably in the order of 75 to 80 marks. In this case a child who is average in MT but very strong in all other 3 subjects may end up with a very much lower aggregate score than another child who is average at maths but very strong in the other 3 subjects.

The pupils who are strong in all 4 subjects will continue to get high PSLE scores and will be less affected by the performance of the cohort.

We live in an unfair/imperfect world. On whether the system is fair one or not ....I reserve my comments.

[justsay]

[quote]Thanks for the explanation. What I actually want to know more is the Skewed Gaussian. Thanks.... :celebrate:[/quote]
Long story...

can check out Wikipedia for the glory details though...[/quote]

Please go to Wikipedia and search for \"skewed normal distribution\"
:lol:[/quote]

okay...thank you ! :lol:

[CrazyDad]

Dharma:

atutor2001:

\"How a single subject can change the assessment order of PSLE students\"

OR

\"T-score is not a fair indication of the Students overall performance.

Hi atutor2001,

Frankly, if you ask me the subject that affects the T-score of the pupils most is MT. With such high % of pupils scoring A and A* in MT ranging from 75% to 82%, the average score is likely to be very high probably in the order of 75 to 80 marks. In this case a child who is average in MT but very strong in all other 3 subjects may end up with a very much lower aggregate score than another child who is average at maths but very strong in the other 3 subjects.

The pupils who are strong in all 4 subjects will continue to get high PSLE scores and will be less affected by the performance of the cohort.

We live in an unfair/imperfect world. On whether the system is fair one or not ....I reserve my comments.

That is why NUS high is setup. They care less about languages and they get all their student through DSA. They do not base on PSLE result.

I still like to good old time, when we just go to the school near by. And parents not even care what is going on, as long as there is no red color in the report book. :celebrate:

[atutor2001]

Dharma:

..... the subject that affects the T-score of the pupils most is MT. With such high % of pupils scoring A and A* in MT ranging from 75% to 82%, the average score is likely to be very high probably in the order of 75 to 80 marks....

Hi Dharma

I fully agreed with your assessment regarding T-score of MT. This happens every year. I understand that the average of Chinese is usually higher than that of Malay and Tamil/Hindi. However, the top score for Tamil/Hindi is usually not high as I have learnt from them that the language is very difficult and most of the students do not use Hindi/Tamil as their mother tongue at home (especially written form). So in a way, those who take Chinese or Tamil/Hindi stand to lose out when it comes to T-score for MT.

That being the case, we are so used to it and do not realise or feel the \"T-score Effect\" of MT when all other papers are \"normal\". However, the \"T-score Effect\" becomes pronounced only when the math paper becomes very tough.

Math is such a subject that when the paper is difficult, there will still be quite a large group of pupils who can attain 100 while the majority will perform way below their normal standards, pulling down the mean and pushing up the T-score of the top students. If ALL of these kids that get 100 are indeed more intelligent than the rest (of course a handful are the real math wizkid) I will gladly accept the ranking from the T-score. Sadly, the truth is, most of the kids that get the 100 marks are not really smarter. The only different is, one has done the questions before and the other has not. So we are rewarding them for being super kiasu, solving questions way beyond the normal curriculum. This will lead to a mad race in future, forcing students to have more practices - not the right way to learn math.

Why does this flaw surface only with math paper? If the English or Science paper becomes very tough, only a selected few will still be able to maintain their high score. They are the real genius in these areas. (we have one in this forum for science :lol: ). Kids cannot attain that level simply by having more practices. They must love and embrass the subject to attain that level. (enjoyment in study). As for the others who just keep practising, they will fair no better. So the T-score will still reflect a reasonably accurate ranking.

Therefore, I personally feel the authority need to be extra careful when it comes to setting the math paper because it can completely distort the overall ranking of the students.

Regards

PS
If a kid is weak in MT but good in the other 3 subjects, their T-score will be greatly pulled down is indeed very true. Perhaps that is why the Chinese paper has been simplified 3 years ago to help this group of pupils. My sister is one of the lucky parents who benefited from the change. Her son's Chinese is far from excellent and yet he got an A* - it is a pleasant joke to me though.

However, they realised that that is not the way to learn Chinese and is now reverting to the old format next year.