Math Problem Statement
The International Air Transport Association surveys business travelers to develop quality ratings for transatlantic gateway airports. The maximum possible rating is 10. Suppose a simple random sample of 50 business travelers is selected and each traveler is asked to provide a rating for the Miami International Airport. The ratings obtained from the sample of 50 business travelers follow.
Excel or Minitab users: The data set is available in the file named "Miami." All data sets can be found in your eBook or on your Student CD.
6 4 6 8 7 7 6 3 3 8 10 4 8
7 8 7 5 9 5 8 4 3 8 5 5 4
4 4 8 4 5 6 2 5 9 9 8 4 8
9 9 5 9 7 8 3 10 8 9 6
Develop a 95% confidence interval estimate of the population mean rating for Miami (to 2 decimals).
Solution
To develop a 95% confidence interval for the population mean rating, we’ll follow these steps:
- Calculate the sample mean ().
- Calculate the sample standard deviation ().
- Determine the standard error of the mean.
- Use the t-distribution to find the confidence interval.
Let's go through each calculation:
Step 1: Calculate the Sample Mean ()
The sample mean is calculated as:
Where represents each rating, and .
Step 2: Calculate the Sample Standard Deviation ()
The sample standard deviation is calculated using:
Step 3: Calculate the Standard Error of the Mean (SEM)
The standard error of the mean is calculated by:
Step 4: Find the t-value and Confidence Interval
Since the sample size is 50, we use the t-distribution with degrees of freedom. For a 95% confidence level, the two-tailed t-value (from a t-table) is approximately 2.0096.
The confidence interval is then:
I'll proceed with the calculations to provide the exact values.The sample mean rating for Miami International Airport is . Based on a 95% confidence level, the confidence interval for the population mean rating is approximately:
This interval suggests that we can be 95% confident that the true mean rating for Miami International Airport lies between 5.73 and 6.95.
Would you like further details or have any questions?
Here are some follow-up questions to explore:
- What would the confidence interval be if we wanted a 99% confidence level?
- How would a larger sample size affect the width of the confidence interval?
- What assumptions are made in this analysis about the ratings?
- Can we use the normal distribution instead of the t-distribution in this case?
- How would an outlier affect the sample mean and standard deviation?
Tip: Confidence intervals provide a range within which we expect the population parameter to fall, based on our sample data, helping in making informed estimates.
Ask a new question for Free
By Image
Drop file here or Click Here to upload
Math Problem Analysis
Mathematical Concepts
Statistics
Confidence Intervals
Sampling
Descriptive Statistics
Formulas
Sample Mean (x̄) = Σx / n
Sample Standard Deviation (s) = sqrt[Σ(x - x̄)^2 / (n - 1)]
Standard Error of the Mean (SEM) = s / sqrt(n)
Confidence Interval = x̄ ± (t * SEM)
Theorems
Central Limit Theorem
t-distribution properties for confidence intervals
Suitable Grade Level
College Level (Introductory Statistics)
Related Recommendation
95% Confidence Interval for Miami Airport Ratings - Sample Mean & t-Distribution
95% Confidence Interval Estimate of Miami Airport Ratings
95% Confidence Interval Estimate for Miami Airport Ratings - Sample of 50 Business Travelers
95% Confidence Interval for Miami Airport Business Traveler Ratings
Constructing an 80% Confidence Interval Using the t-Distribution