Health Statistics H391
Normal curve: visual representation of naturally occurring things.
• Symmetrical
• Mean=median=mode
• No skew
• Asymptotic: does x=/= zero
• 68% of scores fall between -1 and 1 standard deviations
• 95% fall between -2 and 2 standard deviations
• Almost 98 percept fall between -3 and 3 standard deviations.
• For any mean and standard deviation, there is a unique normal curve.
Raw distribution=sample distribution
Sampling w/replacement: new sample, several repeated subjects and new subjects
Means of multiple samples=sampling distributions
• Each value represents an average of multiple scores from multiple samples.
• Standard error: when discussing a population
• Sampling distribution: distribution of a sample of means
• Central limit theorem: sample size increases, sampling distribution mimics normal curve
regardless of original visual representations.
