66. A scientist at UI bio-engineering department is estimating the mean lifetime of a
newly-discovered insect. From a sample of 100 insects, she finds a sample mean of
45 days and a sample standard deviation of 2.5 days. What are the boundaries for a
90% confidence interval for the mean lifetime of the insect?
a. 42.5 to 47.5
b. 44.5875 to 45.4125
c. 40.875 to 49.125
d. 44.51 to 45.49 (ans)
show calculation plz
inferential stat-confidence
2014-04-12 10:01 pm
回答 (2)
2014-04-13 8:37 am
✔ 最佳答案
I think the question is wrong, the boundaries for a 95% confidence interval for the mean lifetime is (d)calculation:
for 90% confidence level,za/2=z0.05=1.96
required confidence interval
=(45-1.96*2.5/√100 , 45+1.96*2.5/√100)
=(44.51 , 45.49)
if 95% confidence interval,
Ans is 44.58875 to 45.41125
2014-04-19 4:20 am
Hin Kei understood the problem, very good! ^^
Thus, the correct answer should be (b).
In the answer, Hin Kei swapped "90%" and "95%" in the explanation.
Thus, the correct answer should be (b).
In the answer, Hin Kei swapped "90%" and "95%" in the explanation.
收錄日期: 2021-04-13 21:17:40
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20140412000051KK00070