24-07-2012, 01:31 PM
Hypothesis Testing
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This modules discusses the concepts of hypothesis testing, including α-level, p-values, and statistical power.
A random sample of n = 25 measurements of chest circumferences from a population of newborns having
= 0.7 inches provides a sample mean of = 12.6 in. Is it likely that the population mean has the value µ = 13.0 in.?
The Process of Testing Hypotheses
The null hypothesis is never proved or established, but is possibly disproved in the course of experimentation.”
“Every experiment may be said to exist only to give the facts a chance of disproving the null hypothesis.”
R.A.Fisher
Design of experiments
Hypothesis Testing Key Concepts
p-value: For a specific test of a hypothesis, the likelihood or probability of observing, under the assumption that the null hypothesis is true, an outcome as far away or further from the null hypothesis than the one observed.
The p-value measures the rareness of an observed outcome, under the assumption that the null hypothesis is true. If the p-value is small, typically p < 0.05, then it is often judged that the null hypothesis is unlikely to be true because, if it were, one would not expect to have observed so unlikely an outcome.