Math Problem Statement
You intend to estimate a population mean μ with the following sample. 82.7, 95.2, 93.2, 56.9, 81.6, 84.7, 85.1, 94.5, 109.5, 72.3 You believe the population is normally distributed. Find the 99% confidence interval. Enter your answer as an open-interval (i.e., parentheses) accurate to two decimal places (because the sample data are reported accurate to one decimal place).
Solution
To calculate a 99% confidence interval for the population mean based on a sample, we follow these steps:
Step 1: Calculate the sample mean ()
The sample data is:
Step 2: Calculate the sample standard deviation ()
Step 3: Find the t-score for a 99% confidence level with degrees of freedom
Using the t-distribution table for a 99% confidence level and 9 degrees of freedom, we find the t-score.
Step 4: Calculate the margin of error (ME)
Step 5: Determine the confidence interval
I'll compute these values.The 99% confidence interval for the population mean based on the given sample is approximately:
This interval suggests that we are 99% confident that the population mean lies within this range.
Would you like further details on this process or have any questions?
Here are five related questions to explore further:
- How would the confidence interval change with a 95% confidence level?
- What would the confidence interval be if we had a larger sample size?
- How does the standard deviation of the sample affect the confidence interval width?
- What assumptions are made when using a t-distribution for confidence intervals?
- How would the interval differ if we assumed the population standard deviation was known?
Tip: Remember, increasing the confidence level increases the interval width, as higher confidence requires capturing more possible values for the population mean.
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Math Problem Analysis
Mathematical Concepts
Statistics
Confidence Interval
Sample Mean
t-Distribution
Formulas
Sample mean: \( \bar{x} = \frac{\sum x}{n} \)
Sample standard deviation: \( s = \sqrt{\frac{\sum (x_i - \bar{x})^2}{n - 1}} \)
Margin of error: \( \text{ME} = t \times \frac{s}{\sqrt{n}} \)
Confidence interval: \( (\bar{x} - \text{ME}, \bar{x} + \text{ME}) \)
Theorems
Central Limit Theorem
Properties of the t-Distribution
Suitable Grade Level
Grades 11-12
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