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Norms and percentile ranks are frequently used to show the subject's characteristics and levels in the test. A comparison between scores of an individual and the norm table(the table of percentile ranks)can roughly show whether his/her standard is above, below or equivalent to the average. Many tests use the percentile ranks to show the position of an individual among subjects of the same group. Students can understand their performance better if their percentile ranks are converted into scores.

A student knows little about his/her own performance of covering 1800 metres in the 9-Minute Endurance Run without referring to the norms. However, if this result is expressed in percentiles or percentile scores, it will be much more meaningful to him/her. For example, if a seventeen-year old boy completes 1800 metres in the 9-Minute Run, he reaches the 75th percentile. This means that he performs as well as or better than 75% of the seventeen-year old boys in the same test item.

Percentiles are computed from a large amount of relevant data whose distribution is normally bell-shaped.


Normal Distribution


 

The difference in performance between percentiles close to the middle (50) is relatively small, but that at both ends is much greater. For example, a 17 year old-boy scoring the 50th percentile in the 9 Minutes Endurance Run covers 1675 metres while another boy scoring the 25th percentile covers 1520 metres. Their difference is 155 metres. However, a boy scoring the 3rd percentile covers 1207 metres. The difference between his distance covered and that of the 25th percentile is 313 metres. Therefore, when converting test results into percentile ranks (scores), they should not be treated as arithmetic means.

The percentile ranks in the norm tables of the Schools Physical Fitness Award Schemes are derived from the results of two surveys on "The Physical Fitness Status of Hong Kong Secondary School Children" conducted by the Hong Kong Childhealth Foundation and the Physical Education Section of the Education and Manpower Bureau between 1998 and 2000. About 4,000 (secondary) and 4,600 (primary) students from 20 local secondary and 23 primary schools took part in the tests respectively. Therefore, when using the percentile ranks for comparison, teachers should bear in mind that they are comparing their students with local secondary and primary students' performance of the year 1998/1999 and 1999/2000 respectively.

Besides, the norms show the overall standard of Hong Kong students rather than the expected performance of individual students. Apart from the inborn factors, students' physical status during the test and the environmental factors of the test should also be considered when interpreting test results.

In the school stage, students are undergoing a growth process but the growth rates of individual children of the same age can be quite different. Results of the test should not be used to predict future performance of individual children in sports. However, participating schools can derive their own norms from the test results of their students and compare their own norms with those of the schemes.