Department

StatisticsCourse Code

STATS 13Professor

Tsiang, MikeLecture

5This

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the 3s strategy!

statistic: compute the statistic from the observed data!•

simulate: indentify a model that represents a chance explanation. repeatedly simulate values of the statistic that •

could have happened when the chance model is true and form a distribution!

strength of evidence: consider whether the value of he observed statistic is unlikely to occur when the chance •

model is true!

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the p value!

proportion of the simulated statistic in the null distribution that are at least as extreme (in the direction of the •

alternative hypothesis) as the value of the statistic actually observed in the research study!

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general guideline but depends on the context !

i.e if its about drugs and health, want the p

value to be way smaller!

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rock paper scissor revisited!

what can we concluded!•

we do not have strong evidence that few er than 1/3 of the time scissor is thrown!◦

but does this mean we can conclude 1/3 of the times scissors is thrown?!◦

what else is plausible!◦

what could we do to have a better chance of getting strong evidence for our alternative hypothesis!◦

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summary!

the smaller the p value the more strong the evidence!•

the null hypothesis is the chance explanation!•

alternative hypothesis is the explanation you're trying to show is true (<, >, =/=)!•

null distribution is the distribution of simulated statistics the represent the chance outcome!•

p-value is proportion of the simulated statistics in the null distribution that are at least as extreme as the value fo •

the observed statistic!

the smaller the p value, the stronger the evidence against the null !•

a p value less than 0.05 provides strong evidence against the null!•

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notation summary!

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