PRESENTATION OF DATA

2. PRESENTATION OF DATA

3. Data should be presented in such a way that data should: • become concise without losing the details • arouse interest in the reader • become simple and meaningful to form impressions • need few words to explain • define the problem and suggest the solution too; and • become helpful in further analysis.

5. Table • A table or a statistical table is a systematic arrangement of related statistical data in columns and rows, with a given predetermined and a well decided objective.

6. Parts of a table • Table number • Title of the table • Head note • Stubs • Captions • Main body of the table • Foot Note • Source of data

7. Title Table no Captions Stubs † * - † ‡ * • Source of data

8. Graphs and Diagrams “A picture is worth a thousand words”

9. They attract a reader's attention to what they are supposed to convey about the data. • Further, they may help us to estimate some values at a glance, and serve as a pictorial check on the accuracy of our solutions.

10. They help in comparing data over time and space. • They are visual aids and have apowerful impact on the people. • Graphs can aid us in uncovering trends or patterns hidden in data, • They help us visualize data- Graphs make data look "alive."

11. Presentation of quantitative, continuous or measured data is through graphs. The common graphs in use are: • Line chart or graph • Histogram • Frequency polygon • Frequency curve • Cumulative frequency diagram • Stem and Leaf plot • Scatter or dot diagram. • Box and whisker plot

12. Presentation of qualitative, discrete or counted data is through diagrams. The common diagrams in use are: • Bar diagram • Pie or sector diagram • Pictogram or picture diagram • Map diagram or spot map.

13. Line graph • A line graph is used to illustrate the relationship between two variables.

16. Time series graph or historigram

17. Polygraph

18. Histogram • It is a graphical presentation of frequency distribution.

19. Reaction mm Frequency Percentage 8-10 24 11.7 10-12 52 25.2 12-14 42 20.4 14-16 48 23.3 16-18 12 5.8 18-20 8 3.9 20-22 14 6.8 22-24 6 2.9 Total 206 100.0 Tuberculin reaction in mm

21. histograms are sensitive to choices we make in the number of class intervals and starting point of the graph.

22. Histograms serve as a quick and easy check of the shape of a distribution of the data. • The shape of the histograms depends on the width and the number of class intervals. • Histograms display grouped data. Individual measurements are not shown in the graphs. • Histograms can adequately handle data sets that are widely dispersed.

23. Frequency Polygon • A frequency polygon is obtained from a histogram by joining the mid-points of the top of various rectangles with the help of straight lines,

25. Frequency Curve • If the points obtained in the case of frequency polygon are joined with the help of a smooth curve, we get a frequency curve

26. Ogives- Cumulative Frequency Curve • The graph of a cumulative frequency distribution is known as cumulative frequencycurve or Ogive. • Since a cumulative frequency distribution can be of 'less than' or 'greater than' type, accordingly, we can have 'less than' or 'greater than' type of ogives.

27. Cumulative Frequency Distribution

29. Scatter or Dot Diagram • It is a graphic presentation, made to show the nature of correlation between two variable characters X and Y in the same persons (s) of group(s) such as height and weight in men aged 20 years, hence it is also called correlation diagram.

30. A line is drawn to show the nature of correlation at a glance

33. Diagrammatic presentation of data • A diagram is a visual form for the presentation of statistical data. • Diagram refers to bars, pictorials, cartograms, spot maps etc.

34. Diagrams may be one dimensional, 2 dimensional, 3 dimensional, pictograms or statistical maps

35. BAR DIAGRAMS • In a bar graph categories into which observa­tions are tallied appear on the abscissa (X-axis) and the corresponding frequencies on the ordinate (Y-axis). • The height of a vertical bar represents the number of observations that fall into a category (or a class).

37. Component Bar Diagram • A sub-divided bar diagram is used when it is desired to represent the comparative values of different components of a phenomenon.

39. Multiple Bar Diagram • A set of bars for a period, place or a related phenomenon are drawn side by side without gap. • Different bars are distinguished by different shades or colours.

41. Pie or Sector Diagram • Degrees of angle denote the frequency and area of the sector. • It gives comparative difference at a glance.

44. Pictograms • These are also known as cartograms. • Pictures are more attractive to laymen than other forms of graphic presentations.

45. For showing population of human beings, we draw human figures.

47. It is a popular method to impress the frequency of occurrence of events to common man such as attacks, deaths, number operated, admitted, discharged, accidents etc. in a population

49. Map diagram or Spot Map • These maps are prepared to show geographical distribution of frequencies of characteristic.