A manufacturer of light bulbs advertises that, on average, its long-life bulb will last more than 5,000 hours. To test the claim, a statistician took a random sample of 100 bulbs and measured the amount of time until each bulb burned out. If we assume that the lifetime of this type of bulb has a standard deviation of 400 hours, can we conclude at the 5% significance level that the claim is true?
Answer to relevant QuestionsIn the midst of labor–management negotiations, the president of a company argues that the company’s blue-collar workers, who are paid an average of $30,000 per year, are well paid because the mean annual income of all ...An automotive expert claims that the large number of self-serve gasoline stations has resulted in poor automobile maintenance, and that the average tire pressure is more than 4 pounds per square inch (psi) below its ...The fast-food franchiser in Exercise 11.43 was unable to provide enough evidence that the site is acceptable. She is concerned that she may be missing an opportunity to locate the restaurant in a profitable location. She ...a. The sample mean and standard deviation from a sample of 81 observations are x̄ = 63 and s = 8. Estimate e with 95% confidence.b. Repeat part (a) with n = 64.c. Repeat part (a) with n = 36.d. Describe what happens to the ...a. After sampling 1,000 members of a normal population, you find x̄ = 15,500 and s = 9,950. Estimate the population mean with 90% confidence.b. Repeat part (a) assuming that you know that the population standard deviation ...
Post your question