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posted by  lanniek on 10/22/2009 6:40:39 PM  |  status: Closed  |  Earned Karma: 25

Confidence Inteval

Course Textbook Chapter Problem Needs by
N/A Intro to Stats, De Veau, Velleman, Bock, 3rd Edition Chapter 19 N/A 10/24/2009 at 3:00:00 PM
Question Details:
1. A pollister wishes to estimaye the true proportion of U.S. voters who oppose capital punishment. How many voters should be surveyed in order to be 95% cinfident that the true proportion is estimated to within 2%?
a. 2401
b. 3382
c. 4145
d. 1692
e. not eestimate of the information is given
2. A recent poll of 1500 new home buyers found that 60% hired a moving company to help them move to their new home. Find the margin of error for this poll if we want 95% confidence in our estimate of the percent of new home buyers who hired movers.
a. 2.08%
b. 5%
c. 4.96%
d. 2.48%
e. 2.95%
3. In a survey of 1,000 television viewers, 40% said they watch network news programs/ For a 90% confidence level, the margin of error for this estimate if 2.5%. If we want to be 95% confident, how will the margin of error change.
a. more confidence requires a wider interval, the margin of error will be larger.
b. more confidence requires a wider interval, the margin of error will be smaller.
c. more confidence requires a more narrow interval, the margin of error will be larger.
d. more confidence requires a more narrow interval, the margin of error will be smaller.
e. There is not enough information to determine the effect on the margin of error.
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Oracle
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posted by Jonpp on 10/22/2009 7:07:21 PM  |  status: Live
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Response Details:
1. α=0.05, Z(0.025)=1.96 (check normal table), E=0.02


2. p=0.6, n=1500


3.b. more confidence requires a wider interval, the margin of error will be smaller.



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