In: Statistics and Probability
What is the difference between a statistic and a parameter? If the Central Limit Theorem is so important what is the key benefit of having a sampling distribution that is normally distributed in research? Explain what is meant by ‘sampling error’. How is this important in statistical analysis?
Statistic is a function of the sample values that describes the sample and does not involve any unknown quantities.
Parameter is any constant that describes the population. When the parameter is specified the entire distribution of the data is known to us.
The sampling distribution bring normal is beneficial because the normal distribution has many good important properties. It is symmmetric unimodal distribution. Moreover it belongs to exponential family. Sample mean for normal distribution is unbiased, efficient and MVUE. It becomes easy to derive properties and reach our conclusions using normal distribution.
In order for our research we do not consider the entire population. We draw a random sample from the population. So the difference or deviations in the estimates because of considering only a part of the population is called as standard error. Many a times this sample may exhibit certain variability within it.. Such variabilities can be determined by sampling error. Moreover large sampling error indicates that the sample is not a proper representative of the population.