The quality-control manager at a compact fluorescent light bulb (CFL) factory ne

Question

The quality-control manager at a compact fluorescent light bulb (CFL) factory needs to determine whether the mean life of a large shipment of CFLs is equal to 7460 hours. The population standard deviation is 840 hours. A random sample of 64 light bulbs indicates a sample mean life of 7, 219 hours. a. At the 0.05 level of significance, is there evidence that the mean life is different from 7460 hours? b. Compute the p-value and interpret its meaning. c. Construct a 95% confidence interval estimate of the population mean life of the light bulbs. d. Compare the results of (a) and (c). What conclusions do you reach? e. Compare the results of parts (a) through (d) to those when the standard deviation is 1, 200 hours. a. Let mu be the population mean. Determine the null hypothesis. H_0, and the alternative hypothesis, H_1. What is the test statistic? What is/are the critical value(s)? What is the final conclusion? A. Reject H_0. There is not sufficient evidence to indicate that the mean life is different from 7460 hours. B. Fail to reject H_0 Fail to reject H_0. Reject_H_0 Reject H_0. There is sufficient evidence to indicate that the mean life is different from 7460 hours. b. What is the p-value?

Explanation / Answer

b) p- value = 2 *P(Z < -2.30) = 2*0.0107 = 0.0214

{you can calculate it from standard normal table or online calculator or software like R or Matlab}

since p-value is less than alpha value ,

we reject the null hypothesis and conclude that there is suffiicent evidence that mean is different from 7460 .

option C) is correct

Related Questions

Navigate

• Browse (All)
• Browse T
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.