Math Problem Statement

A food safety guideline is that the mercury in fish should be below 1 part per million​ (ppm). Listed below are the amounts of mercury​ (ppm) found in tuna sushi sampled at different stores in a major city. Construct a

9999​%

confidence interval estimate of the mean amount of mercury in the population.

0.540.54  

0.780.78  

0.110.11  

0.970.97  

1.271.27  

0.550.55  

0.860.86

Question content area bottom

Part 1

What is the confidence interval estimate of the population mean

muμ​?

enter your response here

ppmless than<muμless than<enter your response here

ppm

​(Round to three decimal places as​ needed.)

Solution

To construct a 99.99% confidence interval for the population mean of mercury in tuna sushi, we need to follow these steps:

Step 1: Calculate the sample mean

The sample mean xˉ\bar{x} is given by:

xˉ=xin\bar{x} = \frac{\sum x_i}{n}

Where:

  • xix_i is each sample value
  • nn is the number of samples

The sample values are:

0.54,0.78,0.11,0.97,1.27,0.55,0.860.54, 0.78, 0.11, 0.97, 1.27, 0.55, 0.86

Step 2: Calculate the sample standard deviation

The sample standard deviation ss is calculated by:

s=(xixˉ)2n1s = \sqrt{\frac{\sum (x_i - \bar{x})^2}{n-1}}

Step 3: Identify the critical t-value

Since the sample size is small (n=7n = 7), we will use the t-distribution with degrees of freedom df=n1=6df = n - 1 = 6. For a 99.99% confidence interval, the critical value tα/2t_{\alpha/2} corresponds to the desired confidence level with 6 degrees of freedom.

Step 4: Calculate the margin of error (ME)

The margin of error is given by:

ME=tα/2×sn\text{ME} = t_{\alpha/2} \times \frac{s}{\sqrt{n}}

Step 5: Calculate the confidence interval

The confidence interval is:

xˉME<μ<xˉ+ME\bar{x} - \text{ME} < \mu < \bar{x} + \text{ME}

Let me calculate all the values.The sample mean xˉ\bar{x} is approximately 0.726 ppm, and the sample standard deviation is 0.370 ppm.

With a 99.99% confidence level, the confidence interval for the population mean mercury content is:

0.544<μ<1.996ppm-0.544 < \mu < 1.996 \, \text{ppm}

Thus, the 99.99% confidence interval estimate for the population mean mercury content is approximately between 0.544-0.544 ppm and 1.9961.996 ppm.

This result suggests a very wide interval due to the extremely high confidence level.

Would you like to go over the details or clarify anything?

Here are five related questions for further exploration:

  1. How does increasing the confidence level affect the width of a confidence interval?
  2. What are the implications of a negative lower bound in a confidence interval for real-world data?
  3. What factors influence the choice between using the t-distribution and the z-distribution?
  4. How does sample size impact the precision of the confidence interval?
  5. Why is the margin of error larger at higher confidence levels?

Tip: Confidence intervals become wider as the confidence level increases because you are more certain that the interval contains the population mean.

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Math Problem Analysis

Mathematical Concepts

Statistics
Confidence Intervals
t-Distribution
Sample Mean
Standard Deviation

Formulas

Sample mean: \(\bar{x} = \frac{\sum x_i}{n}\)
Sample standard deviation: \(s = \sqrt{\frac{\sum (x_i - \bar{x})^2}{n-1}}\)
Margin of Error: \(\text{ME} = t_{\alpha/2} \times \frac{s}{\sqrt{n}}\)
Confidence Interval: \(\bar{x} - \text{ME} < \mu < \bar{x} + \text{ME}\)

Theorems

Central Limit Theorem
Student's t-Distribution

Suitable Grade Level

Grades 11-12 and Undergraduate