Hypothesis testing stats 115, Exercises of Statistics

Download Hypothesis testing stats 115 and more Exercises Statistics in PDF only on Docsity! Homework for Chapter 12 1. The average flight time using a certain flight path between two cities is 5.25 hours. A new flight path between these two cities is being considered. It is hoped that this new path will reduce flight time. A sample of 15 flights using the new flight path is taken. The average time of these sample flights was 4.95 hours and the standard deviation of the sample flights was 0.4 hours. Set up and test the hypothesis that the new path reduces flying time at the .05 level. 3. Test verses , given that a sample of 25 pieces of data had a mean of 4.1 and the data is from a normal distribution with a known standard deviation of .30. Perform this test at the .05 level. 5. A random sample of 8 pieces of data was taken from a normal population. The sample had an average of 82.7 and a standard deviation of 4.4. Perform a .01 level test to determine if the population mean is different than 80. 7. A sample of 10 pieces of data is collected and we wish to perform the level test vs. . The population standard deviation is known to be .25. The sample mean is used to calculate the data z value of . vs. Our Test Statistic is: Reject Ho. The data supports the claim Our Test Statistic is: Fail to Reject Ho. The data does not support the claim vs. Our Test Statistic is: What are Ho and Ha? This is a t-test. What is the value of our test statistic? This is a z-test. What is the value of our test statistic? What type of HT is this? (Z, t, chi-square) What type of HT is this? (Z, t, chi-square) Our properly labeled picture! Our properly labeled picture! Conclusion in words. Conclusion in words. Conclusion? Conclusion? What are Ho and Ha? This is a t-test. What is the value of our test statistic? What type of HT is this? (Z, t, chi-square) Our properly labeled picture! Fail to Reject Ho. The data does not support the claimConclusion in words. Conclusion? a) Determine the p-value. Since we have a right sided test, we need to find the area to the right of 1.23. p-value = Note that we would Fail to Reject Ho at the .05 level. b) If the true population mean is , was an error made in this test? If so, which type? We are being told that the population mean is 4.1. Thus, Ha is true. We Failed to Reject Ho and stayed with Ho. Our data conclusion does not match the truth so TYPE II ERROR c) If the true population mean is , was an error made in this test? If so, which type? We are being told that the population mean is 4.0. Thus, Ho is true. We Failed to Reject Ho and stayed with Ho. Our data conclusion does match the truth so NO ERROR 9. An level test is performed on the computer. The computer gives a p-value of .027. Do we reject or fail to reject Ho? The p-value (.027) is how rare the data is given Ho is true. The - level (.05) is how rare the data needs to be in order to Reject Ho. The data is rare enough. We Reject Ho. 13. Suppose that we are testing Ho: vs. Ha: at the .01 level and we are going to collect 10 pieces of data and . a) Determine the probability of Type II error for the alternative . b) Determine the probability of Type II error for the alternative . c) Determine the probability of Type II error for the alternative . 15. Suppose that we assume the population standard deviation is and we are testing: Answer Answer Our conclusion? Our thoughts?