Answer Happy

A particular brand of tires claims that its deluxe tire averages at least 50,000 miles before it needs to be replaced. From past studies of this tire, the standard deviation is known to be 8,000 miles. A survey of owners of that tire design is conducted. From the 65 tires surveyed, the mean lifespan was 46,500 miles with a standard deviation of 9,800 miles. Using alpha = 0.05, does the data show the real mean is less than the claim? a. Write a null and alternate hypothesis in both words and symbols to test the claim b. Find a 95% confidence interval to test your hypothesis. Show the calculation you used to find the upper and lower bounds of the confidence interval and the final interval. Round all decimal values to 3 decimal places. c. Write a conclusion summarizing your findings. In your summary explain how you used the confidence interval to reject the null hypothesis or fail to reject the null hypothesis. d. Find the p-value (or significance level) associated with sample mean, rounded to 3 decimal places. Include the Excel ENORM.DIST code you used. Round inputs into =NORM.DIST to 3 decimal places NOTE: you may need to use the NORM.DIST output or its complement. e. Write a conclusion summarizing your findings. In your summary, explain how you used the p-value to reject or fail to reject the null hypothesis. Round all values to 3 decimal places. f. Draw a sketch of a normal distribution with u,x, a, and the CL labeled. I