I invited Kethmi Hettige to talk about the Z-score. For those who did A/Ls in Sri Lanka - this is a life deciding equation. Kethmi received her Bachelors in Industrial Statistics and Mathematical Finance from the Faculty of Science, University of Colombo. She is currently doing her PhD in Singapore.
00:00 About Z-score
00:59 Origins of the equation
01:52 Statistical measure
04:30 Mean,SD can be subjective
05:33 Why use it for A/Ls?
06:46 How to calculate it?
10:35 Problem with 2011 A/Ls
11:49 Bell curves
14:03 Biggest assumption with Z-score
16:09 Is it a good method?
20:22 Representative samples
21:35 What determines cutoff marks?
