The confidence interval is 0.028, 0.872
<h3>Given </h3>
862 of 1013 randomly selected adults wear seat belts.
The 95% confidence interval for the proportion of adults who always wear seat belts.
<h3>What is confidence interval?</h3>
A Confidence Interval is defined as a range of values we are sure our true value lies within it.
<h3>What is 95% confidence interval?</h3>
A 95% confidence interval is defined as that if we take 100 different samples and compute a 95% confidence interval for each sample, then approximately 95 of the 100 confidence intervals will contain the true mean value.
= 862/1013 = 0.85
At a 95% confidence interval ,the critical value is ![z_{0.025} = 1.96](https://tex.z-dn.net/?f=z_%7B0.025%7D%20%20%3D%201.96)
The 95% confidence interval for proportion is
![\widehat p +/- z0.025 * sqrt(\widehat p * (1 - \widehat p)/n)](https://tex.z-dn.net/?f=%5Cwidehat%20p%20%2B%2F-%20z0.025%20%2A%20sqrt%28%5Cwidehat%20p%20%2A%20%281%20-%20%5Cwidehat%20p%29%2Fn%29)
![= 0.85 +/- 1.96 * sqrt(0.85 * (1 - 0.85)/1013)](https://tex.z-dn.net/?f=%3D%200.85%20%2B%2F-%201.96%20%2A%20sqrt%280.85%20%2A%20%281%20-%200.85%29%2F1013%29)
![= 0.85 +/- 0.022](https://tex.z-dn.net/?f=%3D%200.85%20%2B%2F-%200.022)
= 0.028, 0.872
The sample should use at least 10 successes and 10 failures.
![n * \widehat p = 1013 * 0.85 = 861 > 10](https://tex.z-dn.net/?f=n%20%2A%20%5Cwidehat%20p%20%3D%201013%20%2A%200.85%20%3D%20861%20%3E%2010)
![n * (1 - \widehat p) = 1013 * 0.15 = 152 > 10](https://tex.z-dn.net/?f=n%20%2A%20%281%20-%20%5Cwidehat%20p%29%20%3D%201013%20%2A%200.15%20%3D%20152%20%3E%2010)
As the sample size is larger, we can use an approximate formula for the standard error.
Learn more on Confidence intervals here:
brainly.com/question/8961482
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