stats

• Statistics


  A branch of science that deals with studies involving collection, presentation, analysis, interpretation, and drawing conclusions from the data
• General purpose of Statistics


  • Research can see what happened in the research study and communicate the results to others
  • Help researcher to answer questions that initiated the research
  • Helps to determine exactly what general conclusions are justified from the specific results
• Two main branches of Statistics

  • Descriptive Statistics
  • Inferential Statistics
• Hypothesis Testing


  An area of inferential statistics, a decision making procedure to find out whether there is a significant differences between a claim about a population and another information obtained about the said population
• Data


  Any pieces of information useful to the researcher
• Two classifications of Data

  • Quantitative
  • Qualitative
• Variable


  A characteristic of a population or sample which make one different from the other
• Four classifications of Variables

  • Continuous variable
  • Discrete variable
  • Independent Variable
  • Dependent Variable
• Parameter


  A value or measure obtained from a population
• Statistic


  A value or measure obtained from a sample
• Four types of Scales

  • Nominal
  • Ordinal
  • Interval
  • Ratio
• Summation notation (Σ)


  The most commonly used notation in statistics, which reads "the sum of" or "the summation of"
• Data collection


  Gathering data from primary and secondary sources
• Secondary sources


  • Newspapers
  • Journals
  • Magazines
  • Government offices
  • Private organizations
  • Establishments
  • Recognized individuals with firsthand information
• Primary sources


  • Government offices
  • Private organizations
  • Establishments
  • Recognized individuals with firsthand information
• Methods of collecting data

  • Interview method
  • Questionnaire method
  • Registration method
  • Experimental method
  • Observation method
  • Texting method
• Interview method


  Researcher makes direct and personal contact with the interviewee and gathers data by asking a series of questions
• Questionnaire method


  Researcher distributes and collects questionnaires either personally or by mail
• Registration method


  Data is gathered from offices concerned, governed by existing laws
• Experimental method


  Used to find cause and effect relationship of certain phenomena under controlled conditions
• Observation method


  Researcher observes subjects individually or in groups to obtain data and information
• Texting method


  Researcher asks or invites individuals to text opinions, issues or brand preferences using their cellphones
• Slovin's formula


  Used to determine sample size: n = sample size, N = population size, e = margin of error
• Non-probability sampling techniques


  • Convenience sampling
  • Quota sampling
  • Purposive sampling
• Probability sampling techniques


  • Lottery sampling
  • Table of random numbers
  • Systematic sampling
  • Stratified sampling
  • Cluster sampling
  • Multi-stage sampling
• Lottery sampling


  Each member of the population is numbered on a piece of paper
• Table of random numbers

  Used to draw numbers for the sample
• Systematic sampling


  Population is numbered and every nth element is selected
• Stratified sampling


  Population is divided into strata (groups) and samples are obtained proportionately from each stratum
• Cluster sampling


  Members of the sample are selected by area, then each area is selected by lottery sampling
• Multi-stage sampling


  Combinations of several random sampling techniques are used to get a sample from a very large population
• Convenience sampling


  Sample is selected because it is convenient for the researcher
• Quota sampling


  Researcher uses proportions of different strata and selections are done using quota
• Purposive sampling


  Researcher selects respondents purposely related or close to him
• Ways of organizing data

  • Grouped data
  • Ungrouped data
• Presentation of data


  • Array form method
  • Textual form method
  • Stem and leaf presentation
  • Tabular form method
  • Frequency distribution table
• Array form method


  Rectangular arrangement of objects in equal rows and columns
• Textual form method


  Also called paragraph method, used for qualitative data or very few numerical data
• Stem and leaf presentation

  Stem shows the first digit, leaf shows the second digit
• Tabular form method


  Statistical tables with table heading, body, stubs, box heads, footnotes and source notes