6.12.2005

Q&A: What's sampling error in mean if...

...a sample of 10 observations is drawn from a population with mean 20.1. The mean of the observations equals 18.3 and the sample standard deviation equals 4.8.

A: Sampling error refers to the difference between a sample statistic and the corresponding population parameter: 18.3 - 20.1 = -1.8

Bonus Points

  • The sampling distribution: A sample statistic itself is a random variable and therefore has a probability distribution.
    • The sampling distribution of a statistic is the distribution of all the distinct possible values that the statistic can assume when computed from samples of the same size randomly drawn from the same population. For example, imagine sampling 10 numbers and computing the mean over and over again, say about 1,000 times, and then constructing a relative frequency distribution of those 1,000 means. This distribution of means is a very good approximation to the sampling distribution of the mean. As the number of samples approaches infinity, the relative frequency distribution approaches the sampling distribution.

Category: Quantitative Analysis > Probability

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