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ID: 3355140 • Letter: #

Question

.eatWebapps/assessment/take/launch.jsp?course assessment id- 165347-1&course; id- 298890 1&new; attempt 1&content; uestion Completion Status: QUESTION 5 am interested in the percent of Americans who will NOT watch the 2016 Presidential Debate. Please calculate a 95% confidence interval for the percent of Americans who will NOT watch the 2016 Presidential Debate based on the sample data shown below. Enter your answer with your lower bound , and your upper bound (Please use decimal format and go to 4 decimal places.) WATCH Planning on Watching the 2016 presidential debate Cumulative 68.9 31.1 100.0 valid | No 6987 3152 689 1000 31.1 10139 QUESTION 6 When you calculate a confidence interval, if you increase your confidence level, what happens to the width of the interval? It would get narrower It would get wider

Explanation / Answer

Ans:

sample proportion=0.311

sample size=10139

z value for 95% Confidence interval is 1.96

95% confidence interval for proportion

=0.311+/-1.96*Sqrt(0.311*0.689/10139)

=0.311+/-0.0090

=(0.3020,0.3200)

b)if we increase confidence level e.g. to 99% ,then z value will be 2.58,so margin of error increases and confidence interval becomes wider.