Lesson 2

• In any statistical investigations it must necessarily be based on accurate data. To ensure the accuracy of data the researcher or investigator must know the right source and methods of collecting them. The methods of data presentation may vary in their efficiency depending on the type of data or information gathered.
• Data collection, organization and presentation of data are equally important activities in any research undertaking. For if the researcher did not collect the data correctly or in appropriate
• Data collected can be classified into two types namely; primary and secondary data. A primary data refers to the information gathered directly from an original source or based on the direct or firsthand experience while secondary data refers to the information, which are previously gathered by previous individual or those that have been acquired through exiting records.
• Primary Data is also called as Primary Sources because they were originally created by someone else for some other purpose than your current research project. They include books, articles, reports, etc., written by others about topics related to your research question.
• Secondary Data is also known as Secondary Sources because they contain information that was compiled or analyzed by someone else for another reason. Examples of secondary sources include government publications, newspaper articles, journal articles, and websites.
• The most common method used in gathering primary data is survey. Surveys are usually conducted using structured questionnaires with closed-ended questions. This means that respondents will only choose one answer per question. Open-ended questions are sometimes included at the end of the questionnaire to allow respondents to express themselves freely.
• Methods of Collecting Data

  1. Direct or Interview Method
  2. Indirect or Questionnaire Method
  3. Registration Method
  4. Observation Method
  5. Experiment Method
• Direct or Interview Method


  it is person-to-person exchange between the interviewee and the interviewer. It provides consistent and more precise information. Disadvantages- Time consuming, Expensive and has limited coverage.
• Indirect or Questionnaire Method


  written responses are given to prepared questions. Questionnaire is a list of question to illicit answers to the problems of the study
• Registration Methods


  a method of gathering information or data is enforced by the law.
• Observation Method


  the investigator observes the behaviour of the subject and their outcomes. The subject usually cannot talk or write and it requires a proper recording of the behaviour at the appropriate time and situation
• Experiment Method


  it is a method of gathering data when the objective is to determine the cause and effect relationship of a phenomena under controlled conditions
• After the collection of data, they need to be processed and organized. In doing so, the researcher should choose the most effective method and highlight the research findings. It is one of the most important parts of research work is the analysis and interpretation of the gathered data. Accuracy will greatly enhance in an orderly and concise method of presentation of the data gathered. This benefits not only the researcher and the reader, but most is the statistician who will make the analysis of the data. Data analysis are easily determined if the data are properly determined.
• Methods of Data Presentation

  1. Textual Form
  2. Tabular Form
• Textual Form


  Presents provides the concise narrative description highlights of a few and important results of the study.
• "Business confidence in Metro Manila continued to deteriorate due to political uncertainties and the slowdown in the economies of the country’s major trading partners. The survey showed that out of 177 respondents, only 23.3 percent said that they were willing to expand this year” (Philippine Daily Inquirer, September 24, 2001)
• Tabular Form


  Presents data in condensed form by arranging them systematically into rows and columns.
• In each row /column, there is at least two cell entries, one that describes the information on one or more cells containing the numerical information. It must be properly labelled with table number and heading
• Tabular arrangement of data by grouping the values into mutually exclusive classes and showing the number of observations falling in each class. The class or categories should not be overlapping.
• Class Boundaries


  Numbers that are halfway between the upper limit of a class and the lower limit of the next class
• Class Mark or Midpoint


  average of the lower and upper limits of a given class interval denoted by capital letter x or simply “X”
• Relative Frequency(RF)


  obtained by dividing the frequency of that class by the total number of observations.
• Relative Percentage (RF%)


  obtained by multiplying the relative frequency by 100%
• Cumulative Frequency (CF)


  The accumulated frequency of a class. Less than CF or Greater than CF
• Graphical


  -Presents the data in pictorial form
• Graphical


  Designed and constructed to attract and hold attention of readers
• Types of Graph

  -Line Graph

  -Bar Graph

  -Pie Graph

  -Pictogram

  -Histogram
• Line Graph


  Useful for showing trends over a period of time
• Bar Graph


  Consist of series of rectangular bars where the length of the bar represents the magnitude to be demonstrated.
• Pie Graph


  provides easy measurement and fast presentation of nominal data divided into a few categories
• Pictogram

  Pictures or symbols are used to represent certain quantity or volume
• Histogram


  A bar graph of a frequency distribution table.
• Sampling Techniques

  • Random Sampling
  • Non-Random Sampling
• Types of Systematic Sampling

  • Stratified Sampling
  • Cluster Sampling
  • Multi-Stage Sampling
• Random Sampling

  Lottery Sampling

  Use of table of random numbers
• Systematic Sampling


  -methods will be develop which we call systematic and draw the sample similar to random sampling by drawing item say multiple of from the sample.
• Stratified Sampling


  population must be first divided into homogeneity to avoid the possibility of drawing samples whose member come only from one stratum. It is often called stratified proportional sampling
• Cluster Sampling


  -sometimes referred to as an area sampling because it is frequently applied on geographical basis. On this basis, districts or blocks of a municipality or city is selected. These districts or blocks constitutes the cluster

  -Reverse of stratified proportional sampling
• Cluster Sampling


  For instance, if a community has a lower, middle and upper income residents living side by side, we may use this community as a source of a sample to study the different socio-economic status. By concentrating on this particular area, we can save time, effort and money
• Multi-Stage Sampling


  – this technique uses several stages or phases in getting the sample.