1. Arrange the data in ascending order: 13, 15, 20, 21, 23, 27, 33, 34, 36
2. Total number of elements (N) = 9
3. Locate the position of the score in the distribution:
- P = (70/100) × N = (70/100) × 9 = 6.3
- Round up to the nearest whole number: 7
4. Value of Dₖ: The 7th value in the sorted list is 33
5. Location of Dₖ: Position 7, observation 33
6. INTERPRETATION:
- The 70th percentile is 33
- Thus, we conclude that 70% of the 9 students scored less than 33 points in their 40-item quiz.
- Moreover, 30% of the 9 students scored more than 33 points in their 40-item quiz.
Parent Tip: Review the logic above to help your child master the concept of percentile worksheet.