Math Problem Statement
Solution
To solve this problem, we need to calculate a 95% confidence interval for the population proportion of adults in city X who own a mobile phone.
Step-by-Step Solution:
-
Define the Sample Proportion:
- Given:
- Total sample size
- Number of people who own a phone
- Sample proportion is calculated as:
- Given:
-
Determine the Confidence Level and Critical Value:
- For a 95% confidence level, the critical value (for a standard normal distribution) is approximately 1.96.
-
Calculate the Standard Error (SE):
- Standard error for the proportion is given by:
- Substituting the values:
-
Calculate the Margin of Error (ME):
- The margin of error is :
-
Find the Confidence Interval:
- The 95% confidence interval is given by:
- Substituting the values:
Answer:
The 95% confidence interval for is approximately:
Would you like more details or have any questions?
Related Questions:
- How would the confidence interval change if the confidence level was increased to 99%?
- What is the effect of a larger sample size on the width of the confidence interval?
- How would we calculate the confidence interval if the sample proportion was unknown?
- How does changing the sample size affect the standard error of the proportion?
- What assumptions are necessary for constructing a confidence interval in this scenario?
Tip:
For a larger sample, the confidence interval becomes narrower, meaning we estimate the true proportion more precisely.
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Math Problem Analysis
Mathematical Concepts
Statistics
Confidence Interval
Proportion
Formulas
Sample proportion \( \hat{p} = \frac{x}{n} \)
Standard Error \( SE = \sqrt{\frac{\hat{p} (1 - \hat{p})}{n}} \)
Confidence Interval \( \hat{p} - ME < p < \hat{p} + ME \)
Theorems
Central Limit Theorem
Suitable Grade Level
Undergraduate Level or Advanced High School
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