MATLAB: An Introduction with Applications
6th Edition
ISBN: 9781119256830
Author: Amos Gilat
Publisher: John Wiley & Sons Inc
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In a random survey of 221 self-employed individuals, 22 reported having had their tax returns audited by the IRS in the past year. Estimate the proportion of self-employed individuals nationwide who have been audited by the IRS in the past year.
(a) Find the 95% confidence interval for the true proportion of self-employed individuals nationwide who have been audited by the IRS in the past year:
( , ) (Use 4 decimals.)
(b) Are the conditions for inference met?
(c) How should this interval be interpreted?
(a) Find the 95% confidence interval for the true proportion of self-employed individuals nationwide who have been audited by the IRS in the past year:
( , ) (Use 4 decimals.)
(b) Are the conditions for inference met?
Yes, because 221 > 30.Yes, because 221(0.5) > 30. Yes, because 221(0.0995) > 10 and 221(1 − 0.0995) > 10.We don't have enough information. It's possible the data are not Normally distributed , so we should proceed with caution.
(c) How should this interval be interpreted?
We are 95% confident that the percent of self-employed individuals nationwide who have been audited by the IRS in the past year is 10.0%.We are 95% confident that a randomly chosen self-employed individual who have been audited by the IRS in the past year will fall inside the above interval. We are 95% confident that the proportion of all self-employed individuals nationwide who have been audited by the IRS in the past year is inside the above interval.We are 95% confident that the proportion of self-employed individuals who have been audited by the IRS in this sample is inside the above interval.
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