In article <[EMAIL PROTECTED]>, Dennis Roberts <[EMAIL PROTECTED]> wrote: >This was posted by someone on the apstat list ... and, seems like an >interesting problem to pass along to you.
============= >A class of 5 students took a test on statistics. The results were Ann - 70, >Belinda - 40, Cal - 40, Daniel - 40 and Erika - 40. The teacher standardised >the scores. Ann earned a z-score of 1.79 (to 2 decimal places). >The next week the same class took another test. Ann studied really hard and >blitzed the test. The results were Ann - 100, Belinda - 40, Cal - 40, Daniel - >40 and Erika - 40. Ann was really proud of her achievement. But then the >teacher standardised the scores. Ann was devastated - her z-score was still >1.79. >Ann decided that studying hard was a waste of time so she decided to watch TV >instead of study. The results on that week's test were predictable: Ann - 45, >Belinda - 40, Cal - 40, Daniel - 40 and Erika - 40. Ann thought that maybe she >should have studied after all. But then the teacher standardised the scores. >Ann was right the first time - studying is a waste of time! Her z-score was >still 1.79. >What gives? >[This remarkable result is from an article in the Australian Senior >Mathematics >Journal, Vol 17, No 1, by Ed Staples One should never "standardize" the data. Anyone who lets statistical methods do the thinking neither thinks nor is correctly using statistics. -- This address is for information only. I do not claim that these views are those of the Statistics Department or of Purdue University. Herman Rubin, Department of Statistics, Purdue University [EMAIL PROTECTED] Phone: (765)494-6054 FAX: (765)494-0558 . . ================================================================= Instructions for joining and leaving this list, remarks about the problem of INAPPROPRIATE MESSAGES, and archives are available at: . http://jse.stat.ncsu.edu/ . =================================================================
