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    Question

    In the context of the Central Limit Theorem (CLT), which

    of the following statements is correct?
    A The CLT states that the distribution of a sample becomes skewed as the sample size increases. Correct Answer Incorrect Answer
    B The CLT applies only when the population distribution is normal. Correct Answer Incorrect Answer
    C The CLT states that the sampling distribution of the sample mean approaches normality as the sample size increases, regardless of the population's distribution. Correct Answer Incorrect Answer
    D The CLT ensures that the population mean and sample mean are always identical. Correct Answer Incorrect Answer
    E The CLT applies to small sample sizes, even if the population distribution is heavily skewed. Correct Answer Incorrect Answer

    Solution

    The Central Limit Theorem (CLT) is one of the foundational principles of statistics. It states that regardless of the shape of the population distribution (whether skewed, bimodal, or uniform), the sampling distribution of the sample mean will approach a normal distribution as the sample size increases. This phenomenon holds true even if the original population distribution is not normal. However, the convergence to normality improves with larger sample sizes, typically when n≥30n \ geq 30 n≥30, which is often cited as a rule of thumb.   For example, consider a population with a skewed distribution, such as household incomes. Individual samples drawn from this population might reflect its skewed nature. However, if you repeatedly take samples and compute their means, plotting these sample means will produce a distribution that becomes increasingly normal as the number of samples grows. This property allows statisticians to apply inferential methods, such as hypothesis testing and confidence intervals, based on the assumption of normality. Why Other Options Are Wrong:  

    • A. The CLT states that the distribution of a sample becomes skewed as the sample size increases:  
    • This is incorrect because the CLT describes how the sampling distribution of the sample mean becomes normal as the sample size increases, not skewed. In fact, larger sample sizes help mitigate the effects of skewness in the population distribution when examining the sampling distribution of the mean.  
      • B. The CLT applies only when the population distribution is normal:  
      This is a common misconception. The CLT does not require the population distribution to be normal. It applies to populations with any shape of distribution, provided the sample size is sufficiently large. This flexibility is one of the theorem's most important features .  
      • D. The CLT ensures that the population mean and sample mean are always identical:  
      This is incorrect because the population mean and the sample mean are not guaranteed to be identical; they are often close, but the sample mean is an estimate of the population mean. The CLT does not imply equality between the two but instead focuses on the distribution of the sample mean.  
      • E. The CLT applies to small sample sizes, even if the population distribution is heavily skewed:  

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