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Unformatted text preview: Statistical significance: An observed effect so large that it would rarely occur by chance is called statistically significant. Significance depends on the alternative hypothesis. The P value for a onesided test is onehalf the P value for the twosided test of the same null hypothesis based on the same data. The twosided P value combines two equal areas, one in each tail of a Normal curve. The onesided P value is just one of these areas, in the direction specified by the alternative hypothesis . It makes sense that the evidence against H is stronger when the alternative is onesided, because it is based on the data plus information about the direction of possible deviations from H . Significance depends on sample size. How important an effect is depends on the size of the effect as well as on its...
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This note was uploaded on 02/27/2012 for the course STAT 121 taught by Professor Patticolling during the Winter '11 term at BYU.
 Winter '11
 PattiColling

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