Wynberg girls high-louise keegan-maths-grade11-statistics cumulative frequency
- 1. Cumulative Frequency Gr 11 Statistics (Activity 8.11)
- 2. Calculating Cumulative Frequency Questions: How many learners: Wrote the test? ii) Scored 7 marks or less iii) Scored less than 6 iv) Scored more than 4 v) Scored 3 marks of more 1 10 1 9 9 8 4 7 7 6 7 5 5 4 3 3 2 2 0 1 Cumulative Frequency Frequency Mark Mark obtained by learners in a test
- 3. Quick Practice Do…Activity 8.11. p198, 2
- 4. Grouped Data <40: rewrite exam Between 40 and 51: write an essay >91: Get A+ 80 or more (less than 91): Get A 1 91 - 100 6 81 – 90 29 71 – 80 35 61 – 70 20 51 – 60 14 41 – 50 7 31 – 40 6 21 – 30 2 11 – 20 0 1 – 10 Cumulative Frequency Frequency Marks Marks for English Exam
- 5. Drawing an ogive Things to remember: Start ogive at (0;0) Plot each point at the end of the group E.g. in the group 0 – 10 use 10 as the x-value Draw with a ‘free hand’ ogive.notebook 91 - 100 81 – 90 71 – 80 61 – 70 51 – 60 41 – 50 31 – 40 21 – 30 11 – 20 1 – 10 Marks Marks for English Exam 120 1 119 6 113 29 84 35 49 20 29 14 15 7 8 6 2 2 0 0 Points Cumulative Frequency Frequency
- 6. Drawing an ogive Things to remember: Start ogive at (0;0) Plot each point at the end of the group E.g. in the group 0 – 10 use 10 as the x-value Draw with a ‘free hand’ ogive.notebook 91 - 100 81 – 90 71 – 80 61 – 70 51 – 60 41 – 50 31 – 40 21 – 30 11 – 20 1 – 10 Marks Marks for English Exam (100;120) 120 1 (90;119) 119 6 (80;113) 113 29 (70;84) 84 35 (60;49) 49 20 (50;29) 29 14 (40;15) 15 7 (30;8) 8 6 (20;2) 2 2 (10;0) 0 0 Points Cumulative Frequency Frequency
- 7. Finding Median and Quartiles with Cumulative Frequency Find an estimate of the: Median Lower Quartile (Q1) Upper Quartile (Q3) Inter-Quartile Range 120 1 91 - 100 119 6 81 – 90 113 29 71 – 80 84 35 61 – 70 49 20 51 – 60 29 14 41 – 50 15 7 31 – 40 8 6 21 – 30 2 2 11 – 20 0 0 1 – 10 Cumulative Frequency Frequency Marks Marks for English Exam
- 8. Finding Median, Quartiles and Percentiles from ogives Find the median Find Q1 Find Q3 What is the IQR Where is the 5 th percentile? How many learners scored less than 65%?