Chapter 20 - Chapter 20 Testing Hypotheses About...

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Chapter 20 Testing Hypotheses About Proportions ActivStats: 20 Read: Chapter 20 Problem : Suppose we tossed a coin 100 times and we obtained 38 Heads and 62 Tails. Is the coin biased? There is no way to say yes or no with 100% certainty. But we may evaluate the strength of support to the hypothesis that "the coin is biased". Testing Hypotheses: 1. Null hypothesis H O : established fact, no change of parameters, a statement that we expect data to contradict 2. Alternative hypothesis H A : new conjuncture, change of parameters, your claim, a statement that needs a strong support from data to claim it. In our problem H O : coin is fair, p = 0.5 H A : coin is biased, p < 0.5 Where p is the probability that the coin turns “Heads” Attitude: Assume that the null hypothesis H O is true and uphold it, unless data strongly speaks against it. Test mechanics: From data compute the value of a proper test statistics . If it is far from what is expected under the null model H O assumption, then we reject H O .
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Chapter 20 - Chapter 20 Testing Hypotheses About...

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