Obtain the 95% confidence interval for the mean difference in improvements of gas mileage and interpret the result.

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Chapter 21, Problem 5E

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Obtain the 95% confidence interval for the mean difference in improvements of gas mileage and interpret the result.

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Let us suppose we have some article reported on a study of potential sources of injury to equine veterinarians conducted at a university veterinary hospital. Forces on the hand were measured for several common activities that veterinarians engage in when examining or treating horses. We will consider the forces on the hands for two tasks, lifting and using ultrasound. Assume that both sample sizes are 6, the sample mean force for lifting was 6.2 pounds with standard deviation 1.5 pounds, and the sample mean force for using ultrasound was 6.4 pounds with standard deviation 0.3 pounds. Assume that the standard deviations are known. Suppose that you wanted to detect a true difference in mean force of 0.25 pounds on the hands for these two activities. Under the null hypothesis, 40 = 0. What level of type II error would you recommend here? Round your answer to four decimal places (e.g. 98.7654). Use a = 0.05. β = i What sample size would be required? Assume the sample sizes are to be equal.…

= Consider the hypothesis test Ho: μ₁ = μ₂ against H₁ μ₁ μ2. Suppose that sample sizes are n₁ = 15 and n₂ = 15, that x1 = 4.7 and X2 = 7.8 and that s² = 4 and s² = 6.26. Assume that o and that the data are drawn from normal distributions. Use απ 0.05. (a) Test the hypothesis and find the P-value. (b) What is the power of the test in part (a) for a true difference in means of 3? (c) Assuming equal sample sizes, what sample size should be used to obtain ẞ = 0.05 if the true difference in means is - 2? Assume that α = 0.05. (a) The null hypothesis is 98.7654). rejected. The P-value is 0.0008 (b) The power is 0.94 . Round your answer to four decimal places (e.g. Round your answer to two decimal places (e.g. 98.76). (c) n₁ = n2 = 1 . Round your answer to the nearest integer.

Consider the hypothesis test Ho: = 622 against H₁: 6 > 62. Suppose that the sample sizes are n₁ = 20 and n₂ = 8, and that = 4.5; s=2.3. Use a = 0.01. (a) Test the hypothesis. Round your answers to two decimal places (e.g. 98.76). The test statistic is fo = i The critical value is f = Conclusion: i the null hypothesis at a = 0.01. (b) Construct the confidence interval on 02/022 which can be used to test the hypothesis: (Round your answer to two decimal places (e.g. 98.76).) i