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Quantitative Methods: Reading #7: Estimation and Inference - Coggle Diagram

- - - - Simple Random Sampling
      - Systematic Sampling
      - Stratified Random Sampling
      - Cluster Sampling
    - - Convenience Sampling
      - Judgment Sampling
  - - - Convenience sampling: Selecting sample data process is based on its ease of access, using data that are readily available. Because such a sample is typically not random, sampling error will be greater.
      - Judgment Sampling: Each observaton is selected from a larger data set by the researcher, baswed on her experience and judgment.
- - - - Sampling distribution of the sample means will be approximately normal ( phân phối chuẩn)
      - The mean of the distribution of all possible sample means = u (the population mean)
      - The variance of the distribution of sample means is:
        
        o^2 / n
- - - - x = sample mean
      - t (alpha/2) = t-reliability factor corresponding to a t-distributed standard random variable with n-1 degrees of freedom, where n is the sample size
        => để tra bảng thì phải "n-1" nhưng công thức vẫn là "n"
      - s/n = the standard error of the sample mean where s (standard deviation of sample) & n (sample size)
  - - - Known Variance
        
        Small Sample (n<30)
        
        Z-statistic
        
        Large Sample (n > = 30)
        
        Z - statistic
      - Unknown Variance
        
        Small Sampe (n < 30)
        
        T - statistic
        
        Large Sample ( n > = 30)
        
        T - statistic (*)
    - - Know Variance
        
        Small Sample (n < 30)
        
        not available
        
        Large Sample (n > = 30)
        
        Z - statistic
      - Unknown Variance
        
        Small Sample (n < 30)
        
        not available
        
        Large Sample (n > = 30)
        
        T - statistic (*)