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# ANALYSING DATA TECHNIQUES

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### ANALYSING DATA TECHNIQUES

1. 1. PART 2.0: ANALYSING DATA TECHNIQUES Outcome 3.0:Produce information in appropriate format fordecision making in an organisational context 3.1 Using data from a given business scenario, prepare a range of graphs using spreadsheet – line, pie, bar charts and histograms, and draw valid conclusions based on the information derived
2. 2. Graphic Presentation of a Frequency Distribution i. HISTOGRAM ii. FREQUENCY POLYGON iii. OGIVE
3. 3. a) HISTOGRAM• similar to bar chart but without the gaps between the bars
4. 4. Histogram• class boundaries are marked on the horizontal axis and class frequencies on the vertical axis represented by the heights of the bars. 25 20 Frequency 15 . 10 5 0 1 2 3 4 5 Class Boundaries .
5. 5. HistogramExample 1: Discrete Data: Score for correctanswer Class Score (x) Freq (f) Boundaries 1–5 3 0.5 - 5.5 6 – 10 4 5.5 - 10.5 11 – 15 7 10.5 - 15.5 16 – 20 2 15.5 - 20.5 21 – 25 5 20.5 - 25.5 26 - 30 3 25.5 - 30.5
6. 6. HistogramExample 1: Discrete Data: Score for correctanswer Frequency of Score for the Correct AnswerNo. of Students 8 7 No. of Students 6 5 4 3 2 1 0 Class 0.5 - 5.5 5.5 - 10.5 10.5 - 15.5 15.5 - 20.5 20.5 - 25.5 25.5 - 30.5 Score for Correct Answer Boundaries
7. 7. b) FREQUENCY POLYGON• line segments connecting the points formed by the intersection of the class midpoints and the class frequency. Frequency Polygon of Scores for the Correct Answer 8 7 6 No.of Students 5 4 3 2 1 0 3 8 13 18 23 28 Score for Correct Answer
8. 8. Frequency Polygon• Add classes with ‘zero frequencies’ at both ends of the distribution to ‘tie down’ the graph to the horizontal scale. Score (x) Mid-point Freq (f) -2 0 1–5 3 3 6 – 10 8 4 11 – 15 13 7 16 – 20 18 2 21 – 25 23 5 26 - 30 28 3 33 0
9. 9. Frequency Polygon Frequency Polygon of Scores for the Correct Answer 8 7 6 No.of Students 5 4 3 2 1 0 -2 3 8 13 18 23 28 33 Score for Correct Answer
10. 10. Frequency Polygon Frequency of Scores for the Correct Answer 8 7 6 No. of Student 5 4 3 2 1 0 -4.5 - 0.5 0.5 - 5.5 5.5 - 10.5 10.5 - 15.5 15.5 - 20.5 20.5 - 25.5 25.5 - 30.5 30.5 - 35.5 Score for Correct Answer
11. 11. c) OGIVE (Cumulative Freq. Polygon)• reports the number and percent of observations that occur less than the upper class boundary• must convert the frequency distribution to a cumulative frequency distribution (F) Upper Class Score (x) Freq (f) F Boundaries 1–5 5.5 3 3 3 6 – 10 10.5 4 7 (3 + 4) 11 – 15 15.5 7 14 (7 + 7) 16 – 20 20.5 2 16 (14 + 2) 21 – 25 25.5 5 21 (16 + 5) 26 - 30 30.5 3 24 (21 + 3)
12. 12. Ogive Score (x) Freq (f) UCB F Cum.% 0 0.5 0 0.0 1–5 3 5.5 3 12.5 6 – 10 4 10.5 7 29.2 11 – 15 7 15.5 14 58.3 16 – 20 2 20.5 16 66.7 21 – 25 5 25.5 21 87.5 26 - 30 3 30.5 24 100.0
13. 13. Ogive Ogive of Scores for the Correct Answer 30 25 Cumulative Frequency 20 15 10 5 0 0.5 5.5 10.5 15.5 20.5 25.5 30.5 Score of Correct Answer
14. 14. Histogram with percentages Frequency of the Scores for Correct Answer 8 120.0 7 100.0 6 80.0 5 Frequency 4 60.0 3 40.0 2 20.0 1 0 0.0 1–5 6 – 10 11 – 15 16 – 20 21 – 25 26 - 30 Scores for Correct Answer