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Unformatted text preview: ect H0, your results are not significant. 7 Z‐Test for a Population Mean To test the hypothesis H0: = 0 based on an SRS of size n from a population with unknown mean and known standard deviation , Z0 x 0
/ n compute the test statistic: the P‐values for a test of H0 against: Ha: > 0 is P( Z Z0) Ha: < 0 is P( Z Z0 ) Ha: 0 is 2* P( Z  Z0 ) These P‐values are exact if the population is normally distributed, and are approximately correct for large n in other cases. 8 EXAMPLES 1. Last year the government made a claim that the average income of the American people was $33,950. However, a sample of 50 people taken recently showed an average income of $34,076 with a population standard deviation of $324. Is the government’s estimate too low? Conduct a significance test to see if the true mean is more than the reported average. Use an =0.01. 2. An environmentalist collects a liter of water from 45 different locations along the banks of a stream. He measures the amount of dissolved oxygen in each s...
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 Spring '08
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 Statistics

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