Unit IV Methods of Data Presentation PDF

Unit IV METHODS OF DATA PRESENTATION Learning Outcomes At the end of the topic the students should be able to: 1. choose the appropriate method for particular type of data. 2. construct statistical tables 3. draw the graph for particular types of data 4.1 The textual...

Unit IV METHODS OF DATA PRESENTATION Learning Outcomes At the end of the topic the students should be able to: 1. choose the appropriate method for particular type of data. 2. construct statistical tables 3. draw the graph for particular types of data 4.1 The textual form or paragraph form is utilized when the data to be presented are purely qualitative or when very few numbers are involved. Generally, this method is not desirable when too many figures are involved as the reader may fail to grasp the significance of certain quantitative relationships, but becomes an effective device when the objective is to call the reader’s attention to some data that require special emphasis. Example 1: “ At the last count, 38 airlines were operating BOEING 707’s, 720’s and 727’s over the world’s airlines. The far –flung Boeing fleet has now logged an estimated1,803,740,000 miles ( 2,885,948,000 km ) and has amassed approximately 4,096,000 revenue flight of 71.6 million “. Example 2: While the Philippines is considered a good achiever in Education, having a high literacy rate, disturbing problems abound. Our literacy rate, for instance, is stagnating.31 of 73 provinces have a literacy rate below the national average, among them, tribal communities in Mindanao and the Cordilleras. In 1983 the number of out of 31 school children was estimated at 1.25 million; most of them belong to the poorest families. About one-third of those who enter first grade do not reach sixth grade; because of repetitions, the average years spent in the elementary grades is 8.5. But although this is so, the number of high school none-enrollees is increasing at a faster rate. 4.2 The Tabular Form A more effective device of presenting data is by means of statistical tables. People who want to make some comparisons and draw relationships usually find the tabular arrangement more convenient and understandable than the textual presentation. A statistical table has four essential components: the table heading, body, stubs and columns captions or box heads. The table heading shows the table number and the title. The table number serves to give the table an identity while the title briefly explains what are being presented. The body is the main part of the table. It contains the quantitative information. In the body of the table, classifications or categories are found at the left. These are referred to as stubs. The stubs describe the data found in the rows of the table. At the top of each column in the table is a designation n identifying what are contained in that particular column. Such designation is called a caption or box head. In addition to the four essential parts, a table may have a prefatory note which is placed just below the title, one or more footnotes which may appear just below the bottom line of a table and source note which indicates whether the data were taken from publication, or were supplied by someone. Table Heading 32 4.3 The Graphical or Pictorial Form Among the different methods of presenting data, the graph or chart is perhaps the most effective device for attracting people’s attention. Readers who look for comparison and trends may skip statistical tables but may pause to examine graphs. A graph should have a title. There are various types of graphs among the types are, line graph, bar graph and pie graph. 4.3.1 Line Graph This graph is an effective device to portray changes in values with respect to time. It is similar to the Cartesian coordinate system where the categories or time periods are chronologically arranged along the horizontal axis and the relevant values are plotted along the vertical axis. Variations in the data are indicated by series of line segments formed by joining consecutive points plotted above the categories. Example 1: 33 Example 2: 4.3.2 Bar Graph 34 This graph consists of bars and rectangles which are drawn either horizontally or vertically depending on the type of data and the purpose of comparison. Generally, vertical bars are used for chronological comparisons while horizontal bars are employed to show categorical comparisons. The individual bars depict the different categories in the data. The height or length of the bar corresponds to the value attached to each category. Example 1: Example 2: Example 3: 35 4.3.3 Pie Graph or Pie Chart This is appropriate for portraying the relative magnitudes of the component parts of a whole. It is constructed by dividing a circle ( a pie) into sectors, each sector having a size proportional to the percentage it represents. The number of degrees of the central angle of the sector representing a component using the formula No. of degrees = percentage x 3.6 0 3.60 is 1 % of 360 Example 1: Let us show the pie chart of the data below: Table 3.1. Occupation of fathers of preschool-age children Father’s Occupation Frequency (f) Professional 21 Craftsman 19 Manager 6 36  Proprietor 7 Other 7 TOTAL 60 How to find the percentage for each category in table 3.1 Professional 21/60 =.35 x 100% = 35 % 35% of 3600= 1260 Proprietor 7/60=.1167x100%=11.7 % 11.67% of 3600= 420 Craftsman 19/60 =.3167x100%= 31.7% 31.67% of 3600=1140 Other 7/60=.1167 x 100 % = 11.7 % 11.67 % of 3600=420 Manager 6/60 =.1 x 100% = 10 % 10% of 3600= 360 Other 11.7% Proprietor 11.7% Professional 35% Manager 10% Craftsman 31.7% Fig.1 Pie Chart for the occupation of fathers of pre-school age children Example 2: 37  Legend: Exercises: A. Identify which of the methods of data collection is appropriate for the following data: 1. Number of companies belonging to a certain industry in the National Capital Region. 2. Ages and present occupation of the heads of 1,000 households in a community. 3. Educational attainments of a random sample of 20 bank managers. 4. Opinion of a sample of ten businessmen regarding the present political situation. 5. Number of car owners in 2019. B. State which graph would most appropriately represent the given situation: 1. The number of students enrolled at a State University for each year during the last eight years. 2. The means of transportation the students use to get to school. 3. The percentage of votes each of the four candidates received in the last election. 4. The frequency of each type of crime committed in a city during the year. 5. The cost of living for a 5-person low- income family at maintenance level in Manila broken down Into food, clothing, shelter, fuel and light components estimated for each year 2000-2005. 38