All About T-Score

[verykiasu2010]

MOE Hater:

verykiasu2010:

I think it is not possible to have t-score of more than 75 for any subject.


Max t-score for each subject is 75. Max aggregate is 300.

http://road-to-psle.blogspot.com/2007/11/how-psle-aggregate-and-t-scores-are.html

Of course it is possible to get more than 75

Please illustrate with an example

thank you

[atutor2001]

verykiasu2010:

Please illustrate with an example


thank you

The formula for T-score = 50 + 10 x (X-Y)/Z

X = Raw score of student
Y = Average Score of the whole cohort
Z = Standard Deviation* (SD)

So if Z is very very small i.e. near zero, then (X-Y)/Z approaches infinity.

Mathematically, there is no upper limit to the T-score.

[Sun_2010]

verykiasu2010:

Please illustrate with an example

thank you

To take a practical example
Say for tough Maths paper and a smart child, the
mean = 60,
SD= 12
raw score = 96

T- Score = 50 + (96-60)10/12
= 80

[Sun_2010]

My 2 cents-

A small increase in SD has a larger impact on the T-score than in a simialr increase in mean.

Say the same example as above with mean increase by 3
mean = 63
SD= 12
raw score = 96
T- Score = 50 + (96-63)10/12 = 77.5

now with SD increase by 1 point
mean = 60
SD= 13
raw score = 96
T- Score = 50 + (96-63)10/12 = 77.69

So the impact of mean increase by 3 is affects slightly more than SD increase by 1.

[verykiasu2010]

thank you all for the wonderful examples !


what has been the range of the SD and the mean for each subject in recent years ? any one ?

[Augmum]

MOE Hater:

verykiasu2010:

I think it is not possible to have t-score of more than 75 for any subject.


Max t-score for each subject is 75. Max aggregate is 300.

http://road-to-psle.blogspot.com/2007/11/how-psle-aggregate-and-t-scores-are.html

Of course it is possible to get more than 75

regarding this issue whether is it possible to get over T-score aggregate of 300 or beyond 75 T-score for each subject,
although theoretically it may seem possible from the equation but maybe practically in PSLE , not feasible
as i had seen it on a slide presented by a Primary school (elite sch)to Parents that the max T-score for each subject is 75
and the max aggregate T-score is 300
(i tried to google it but could not find now as it was a few years ago)

[atutor2001]

Augmum:

regarding this issue whether is it possible to get over T-score aggregate of 300 or beyond 75 T-score for each subject,

although theoretically it may seem possible from the equation but maybe practically in PSLE , not feasible
as i had seen it on a slide presented by a Primary school to Parents that the max T-score for each subject is 75
and the max aggregate T-score is 300
(i tried to google it but could not find now as it was a few years ago)

T-score can definitely go over 75. The most likely subject for t-score above 75 is math. Let say the mean for math is 70 and the standard deviation is 20 (very big in my opinion), a top student with 100 marks will get a t-score of 70+10(100-70)/20 = 85.

Even if the mean is only 60 (too low in my opinion) and the standard deviation remaining as 20, a top student with 100 marks will still get a t-score of 80. That is why it is very important to do well for subjects where the mean is high.

Schools that presented T-score of 75 per subject and 300 for the total, probably, is using the general average they have been observing. I also believe that moderation is made so that the T-scores are around that range.

[Augmum]

atutor2001:

T-score can definitely go over 75. The most likely subject for t-score above 75 is math. Let say the mean for math is 70 and the standard deviation is 20 (very big in my opinion), a top student with 100 marks will get a t-score of 70+10(100-70)/20 = 85.

Even if the mean is only 60 (too low in my opinion) and the standard deviation remaining as 20, a top student with 100 marks will still get a t-score of 80. That is why it is very important to do well for subjects where the mean is high.

Schools that presented T-score of 75 per subject and 300 for the total, probably, is using the general average they have been observing. I also believe that moderation is made so that the T-scores are around that range.

btw, the formula is T = 50 + 10(X - Y) / Z
and not what u have stated 70 + 10(100-70)/20
if according to yr mean for math is 70 and SD is 20 shd work out to be
50+ 10(30)/20 =65 not 85

[atutor2001]

Augmum:

btw, the formula is T = 50 + 10(X - Y) / Z

and not what u have stated 70 + 10(100-70)/20
if according to yr mean for math is 70 and SD is 20 shd work out to be
50+ 10(30)/20 =65 not 85

My apology, got it mixed up.

[Augmum]

atutor2001:

My apology, got it mixed up.

it's ok....no need to aplogise....
just wanna to tell u that there's an error in the formula.