Thursday, November 18, 2010

Eleven Plus Percentiles

Standardised Scores and Percentiles

Standardised Scores range comfortably between 70 and 130. A mean of 100 is average. Naturally there are children who are able to climb to scores over 130. Some children will achieve these outstanding scores through excellent support at school, others through wonderful parents and some through good preparation. Some lucky children have a combination of outstanding ability, amazing parents and miraculous tuition.

When a score goes above 115 and below 85, then the scores are a standard deviation from the mean of 100. The children who are well above 115 and well below 85 can be two standard deviations from the mean. The word deviation in this sense is how far the score is from the average of 100.

A percentile, however, gives different information about a child’s performance in comparison with other children. A percentile describes how many children are on or below a score.

A standardised score in the 75th percentile suggests that the result is as well as or better than 75 out of every hundred children.

A score of 130 and above is reached by only 2.27% of the population.

Standardised Score 130
Interpretation Excellent
Deviation >+2
Percentile Score >98
Percentage of the Population 2.27. (How you find 0.27 of a child?)

Standardised Score 115
Interpretation High Average
Deviation >+1
Percentile Score >83
Percentage of the Population 68.26 – between 85 and 115.

Your child may be more interested to hear that he or she is better than 75% of the other children taking the same test.