A 95% confidence interval for the true mean lifetime of batteries from a new and

Question

A 95% confidence interval for the true mean lifetime of batteries from a new and cheaper supplier was determined to be (85.5, 93.9) hours. If it is required to have a more accurate (i.e., shorter) confidence interval for the mean, how could this be obtained? By taking a larger sample, or by allowing a lower level of confidence (eg 90%). By taking a smaller sample, or by allowing a higher level of confidence (eg 99%). O The length of the confidence interval will be the same regardless of the size sample and the level of confidence. By taking a smaller sample, or by allowing a lower level of confidence (eg 90%). By taking larger sample, or by allowing a higher level of confidence (eg 99%).

Explanation / Answer

The length of the confidence interval will shorter if the sample size increases or the confidence interval becomes 90%. The length of confidence interval is inervertly proportional to root of number of sample size and the value of z decreases with increase in level of significance. Thus, option 1 is correct.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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