Math Problem Statement
A high school guidance counselor has a pamphlet that says that 35% of all high school students go to a community college after graduation. In a survey of 275 randomly selected high school seniors, 116 replied that they planned to go to a community college in the fall. Use a 95% confidence interval to test and see if the pamphlet needs updating. Based on this sample, use your calculator to construct a 95% confidence interval for the proportion of all high school seniors who plan to go to a community college in fall. Round your answers to the nearest tenth of a percent.
Solution
To determine if the pamphlet needs updating, we can construct a 95% confidence interval for the proportion of high school seniors planning to attend a community college. Here's the step-by-step process:
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Calculate the sample proportion ():
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Calculate the standard error (SE) for the proportion:
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Determine the critical value (z) for a 95% confidence interval: The critical value for a 95% confidence interval is approximately 1.96.
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Calculate the margin of error (ME):
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Construct the confidence interval: This gives us:
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Convert the confidence interval to percentages:
Conclusion:
The 95% confidence interval for the proportion of high school seniors planning to attend a community college is approximately to . Since the pamphlet states that 35% of students go to a community college, and this value is not within the confidence interval, there is evidence to suggest that the pamphlet may need updating.
Would you like more details or have any questions?
Here are 5 questions you might consider next:
- How do you interpret the results of a confidence interval?
- What steps can be taken if the confidence interval does not align with the stated proportion?
- How do you calculate a sample size needed for a desired margin of error?
- What are the assumptions underlying the use of confidence intervals?
- How can confidence intervals be used in other fields or scenarios?
Tip: Always ensure the sample size is sufficiently large to provide an accurate estimate when constructing confidence intervals.
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Math Problem Analysis
Mathematical Concepts
Statistics
Confidence Intervals
Proportions
Formulas
Sample proportion formula
Standard error formula
Margin of error formula
Theorems
Central Limit Theorem
Suitable Grade Level
Grades 11-12
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