1. Chapter 3 Percentiles

2. Standard Scores A standard score is a score derived from raw data and has a known basis for comparison. A standard score is a score derived from raw data and has a known basis for comparison. Standard scores allow us to Standard scores allow us to Evaluate raw scoresEvaluate raw scores Compare two data sets that are based on different units of measurement (time, distance)Compare two data sets that are based on different units of measurement (time, distance)

3. Standard Scores Percentiles: the distribution is divided into 100 equal parts with the mean at the 50 percentile. Percentiles: the distribution is divided into 100 equal parts with the mean at the 50 percentile. Quartile: the distribution is divided into 4 equal parts with the mean between the 2 & 3 quartile. Quartile: the distribution is divided into 4 equal parts with the mean between the 2 & 3 quartile. Decile: the distribution is divided into 10 equal parts with the mean between the 5 & 6 decile. Decile: the distribution is divided into 10 equal parts with the mean between the 5 & 6 decile.

4. What is the percentile rank for a score of 6? How many scores fall at or below a 6? (9 scores) 9/15 = 60%

9. Formulas used to calculate percentiles from grouped frequency tables