math prob & statics. Standard deviation
Question Description
(17,18,20) Use t-distribution where the population standard deviation, σ, is not known. you are given the sample mean and the sample standard deviation. In problem 21 use the standard normal distribution, note the critical value for "tc" depends on the sample size of n.
17. commute time: In a random sample of 8 people, the mean time to commute to work was 35.5 mins and the (sample) standard deviation time was 7.2 minutes. find the margin of error and construct the 95% confidence interval.
18. driving distance: in a random sample of 5 people, the mean driving distance to work was 22.2 miles and the (sample) standard deviation distance was 5.8 miles. find the margin of errorand construct the 95% confidence interval.
20. computer repairs: in a random sampling of seven computer repairs, the mean repair cost was $110.00 and the (sample) standard deviation was $44.50. find the margin of errorand construct the 95% confidence interval.
21. #17 revised (commute time) : after reaserching commute times, you find that the population standard deviation time is actually 9.3 minutes. repet 17 using the standard normal tables with appropriate calculations(not from the t-distribution) and compare problem 17.
the professor gave us this take home extra credit... and im lost
This question has not been answered.
Create a free account to get help with this and any other question!
Brown University
1271 Tutors
California Institute of Technology
2131 Tutors
Carnegie Mellon University
982 Tutors
Columbia University
1256 Tutors
Dartmouth University
2113 Tutors
Emory University
2279 Tutors
Harvard University
599 Tutors
Massachusetts Institute of Technology
2319 Tutors
New York University
1645 Tutors
Notre Dam University
1911 Tutors
Oklahoma University
2122 Tutors
Pennsylvania State University
932 Tutors
Princeton University
1211 Tutors
Stanford University
983 Tutors
University of California
1282 Tutors
Oxford University
123 Tutors
Yale University
2325 Tutors