Asked by Faustine Hudson on Jun 10, 2024
Verified
In November 2018, 50,000 people living in the United States were asked whether they had a computer at home.43,128 answered yes, they had a computer at home.There were 326,766,748 people living in the United States at the time of the survey.Determine an interval with 99% confidence for the number (how many) of people living in the United States who have a computer at home.
A) 281,851,351 to 281,860,174
B) 280,856,020 to 282,849,297
C) 280,561,930 to 283,143,387
D) 281,852,005 to 281,861,808
Confidence Interval
A range of values, derived from sample data, that is likely to contain the value of an unknown population parameter.
Population
In statistics, the entire set of individuals or items from which samples can be drawn for analysis.
- Gain insight into the procedure for developing a confidence interval concerning a population proportion.
- Develop the skill to apply confidence intervals to scenarios encountered in the real world.
Verified Answer
AL
Austin LutherJun 11, 2024
Final Answer :
C
Explanation :
To find the interval with 99% confidence, we will use the following formula:
$\text{Confidence Interval} = \text{Sample Estimate} \pm \text{Margin of Error}$
The sample estimate is the proportion of people who have a computer at home, which is:
$\hat{p} = \frac{\text{Number of people who have a computer at home}}{\text{Total population surveyed}} = \frac{43,128}{50,000} = 0.86256$
The margin of error can be found using the formula:
$ME = z^* \times \sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$
where $z^*$ is the critical value from the standard normal distribution corresponding to a 99% confidence level, which is 2.576, and $n$ is the sample size (50,000). Plugging in the values, we get:
$ME = 2.576 \times \sqrt{\frac{0.86256(1-0.86256)}{50,000}} \approx 0.007$
Therefore, the interval estimate is:
$0.86256 \pm 0.007$
To find the number of people living in the United States who have a computer at home, we multiply the interval estimate by the total population:
$326,766,748 \times (0.86256 \pm 0.007) \approx 280,561,930$ to $283,143,387$
Therefore, the best choice is C, which is the interval estimate calculated above.
$\text{Confidence Interval} = \text{Sample Estimate} \pm \text{Margin of Error}$
The sample estimate is the proportion of people who have a computer at home, which is:
$\hat{p} = \frac{\text{Number of people who have a computer at home}}{\text{Total population surveyed}} = \frac{43,128}{50,000} = 0.86256$
The margin of error can be found using the formula:
$ME = z^* \times \sqrt{\frac{\hat{p}(1-\hat{p})}{n}}$
where $z^*$ is the critical value from the standard normal distribution corresponding to a 99% confidence level, which is 2.576, and $n$ is the sample size (50,000). Plugging in the values, we get:
$ME = 2.576 \times \sqrt{\frac{0.86256(1-0.86256)}{50,000}} \approx 0.007$
Therefore, the interval estimate is:
$0.86256 \pm 0.007$
To find the number of people living in the United States who have a computer at home, we multiply the interval estimate by the total population:
$326,766,748 \times (0.86256 \pm 0.007) \approx 280,561,930$ to $283,143,387$
Therefore, the best choice is C, which is the interval estimate calculated above.
Learning Objectives
- Gain insight into the procedure for developing a confidence interval concerning a population proportion.
- Develop the skill to apply confidence intervals to scenarios encountered in the real world.
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