Thursday, January 10, 2008

The dumb main stream media again

See this news item. Here is what the article claims.
Gourav Bhattacharya of Mumbai knows how to bell the CAT. He - like only 10-odd other management aspirants all over India - has scored a 100 percentile in the entrance examination to the Indian Institutes of Management.

I am not an expert in calculating percentiles, but I know couple of things for sure. When scores are represented as percentiles, there would be always one person who gets the top percentile.

I am not even sure that anybody can get 100 percentile. As per the percentile rank definition from wikipedia
The percentile rank of a score is the percentage of scores in its frequency distribution which are lower. For example, a test score which is greater than 90% of the scores of people taking the test is said to be at the 90th percentile.

As per above definition, one can not get 100 percentile because that would mean that your score is greater than the score of 100% of the people taking test, that would be impossible because you are also part of 100%.

2 comments:

  1. I guess they would be rounding off the percentile score to 2 decimals. If this is the case, all candidates who have secured above 99.995% would get 100.00%. Given that 2.25 lakh students have written the test, this comes to about 11 students which matches with the news item statement "... like only 10-odd other management aspirants ...".

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  2. Yes, that makes sense. But I would still prefer that they say "So and so has got the first rank in CAT". The way it is written, I believe they are confusing 100th percentile with 100% marks.

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