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STATISTICS CHAPTER 1 - Coggle Diagram

- - - - Collecting
      - Organizing
      - Summarizing
      - Presenting
        
        Data/information in a convenient
        and informative
        way to assist in more
        effective decision
      - Interpreting
      - Analyzing
- - - - gender ; male/female
      - Grade : A,B,C
      - Race ; Malay/Chinese/etc
      - Marital status : single/married
  - - - Assume only exact values ( no of student/total income/shoes size etc) - NO decimal numbers
    - - Express in a certain degree of accuracy. Example : Distance travelled litters of petrol, weight an height - involved decimal numbers
  - - - Population - 120,000 students in Terengganu
      - Sample - 1500 students in Dungun High School
      - Element - Student
      - Variable - Height of students
- - - - Advantages
        
        Satisfy the research objectives
        
        More up to date
      - Disadvantages
        
        Very Costly
        
        Time Consuming
        
        Sensitive data is difficult to collect directly from respondents.
    - - Advantages
        
        Easy to obtain
        
        Less Costly
        
        Can obtain in large quantity
      - Disadvantages
        
        Data might not satisfy the research objective
        
        There might be errors committed by the original researchers
  - - - Ordinal - Categorical as well as essence or order (Arrange in certain order ) Example : level of education : 1 = Primary, 2 = Secondary , 3= University , 4= Post-Graduate
      - Interval - Categorical has order that can describe " hoe much more or how much less" of a characteristic and has the existence of an "arbitrary xero point" Example : Level of satisfaction, temperature.
      - Nominal - Qualitative as well as categorical ( Gender 1= male, 2 = Female
      - Ratio - Consist of all characteristics discuss above plus another characteristics of absolute (true)zero point ( Number with starting point) Example - height of students.
- - - - Data Collected from all elements
      - Data are more complete
    - - Very costly and time consuming
      - Result would be outdated
  - - - Less Costly and less time
      - Result up to date
    - - Data not collected from all elements
      - Data are less complete
    - - Random Sampling ( Probability Sampling) - Every elements in the population has equal chance to be selected as sample.
        
        Simple Random Sampling (SRS) ( Sampling frame must be available)
        
        Methods
        
        Lucky Draw method
        
        Random numbers
        
        Systematic Random Sampling (SYRS) - Sampling frame must be available - how to collect sample)
        
        Step :
        
        Identify the population size N, and the sample size, n
        
        Obtained the range, k by dividing the population size by the sample size,
        Sampling interval k= N/n
        
        Randomly select one element from the first k elements in the list ( Using SRS). Suppose the r th element is selected.
        
        Lastly, sample every k th element in the population begins with the r element until a sample of size n obtained ( Refer note ch 1 page 4)
        
        Advantages
        
        Every elements has equal chance to be selected
        
        Disadvantages
        
        Difficult to use
        
        In order to get a good sample, population must be properly arranged
        
        Stratified Random Sampling
        
        Applicable for population that is categorized such as according to sex, races, etc
        
        Characteristics of the population
        
        Elements in each stratum are homogeneous
        
        Elements between the strata are heterogeneous
        
        Advantages
        
        Every element has equal chance to be selected
        
        Suitable for categorized population
        
        Disadvantages
        
        Difficult to use
        
        Cluster Sampling
        
        Applicable for a population that is divided into homogeneous or similar cluster
        
        Element in the cluster are heterogeneous
        
        How to use
        
        a population is divided into cluster using naturally occurring geographic or other boundaries.
        
        Then clusters are randomly selected
        
        A sample is collected by taking all elements in the selected clusters
        
        Advantages
        
        Suitable for a population that is quite large
        
        Suitable for clustered population
        
        Disadvantages
        
        Difficult to ensure that cluster are similar / homogeneous
        
        Multi-Stage Sampling
        
        Suitable for a large population
        
        Selection done by stages
      - NON- Random Sampling ( Non-Probability Sampling) -Not all elements in the population has equal chance to be selected as sample
        
        a. Quota Sampling - Suitable to be used if sampling frame not available and in market research
        
        Example : A group researcher planned to survey 120 house owners in Dungun who have been using sharp washing machines for more than 2 years. Discuss
        
        The numbers allocated for each group of respondents is based on the population statistics. The researchers has the flexibility to choose whoever he wants as long as the specifications set are met
        
        Convenience Sampling - The researcher has the flexibility to select anybody that they wants or meets until the required sampled is obtained
        
        Judgmental Sampling - The researcher selects a respondent whom he thinks has a certain characteristics that he wants to study
        
        Snowball Sampling - An initial group of respondent is selected usually at random. After being interviewed, these respondents are asked to identify others who belong to the target population of interest.
- - - - Produce highest response rate
      - Explain unclear questions
    - - Very costly & time consuming
      - interviewers must be properly trained
  - - - Less cost & less time
      - Can contact respondents several times
    - - Appropriate only for population with telephones
      - Respondents might refuse to cooperate
  - - - Less Costly
      - Can be used in any population size
    - - Response rate very low
      - Ensure when the questionnaires shall come back
  - - - Data obtained very accurate
      - The access of information is not affected by the respondents
    - - Very costly and time consuming
      - The observer needs to be highly skilled and unbiased