Question

What is the empirical rule?

		A rule for determining the average of a normal distribution based on the standard deviation.
		A rough estimate of how different the sample and population means should be for the result to be statistically significant.
		A guideline of how one should gather empirical data.
		A calculation rule for the confidence interval.
		None of these

Answer 1

Solution:

Given that:

None of these

The empirical rule, also referred to as the three-sigma rule or 68-95-99.7 rule, is a statistical rule which states that for a normal distribution, almost all data falls within three standard deviations (denoted by σ) of the mean (denoted by µ). Broken down, the empirical rule shows that 68% falls within the first standard deviation (µ ± σ), 95% within the first two standard deviations (µ ± 2σ), and 99.7% within the first three standard deviations (µ ± 3σ).