QQuestionAnatomy and Physiology
QuestionAnatomy and Physiology
A sample of 35 different payroll departments found that employees worked an average of 240.6 days a year. If the population standard deviation is 18.8 days, find the 90% confidence interval for the average number of days μ worked by all employees who are paid through payroll departments.
- 232.4 < μ < 248.8
- 230.9 < μ < 250.3
- 236.8 < μ < 244.4
- 235.4 < μ < 245.8
6 months agoReport content
Answer
Full Solution Locked
Sign in to view the complete step-by-step solution and unlock all study resources.
Step 1: First, we need to find the margin of error for the 90% confidence interval.
where $z$ is the z-score corresponding to the desired confidence level, $\sigma$ is the population standard deviation, and $n$ is the sample size.
The formula for the margin of error for a population mean is:
Step 2: For a 90% confidence interval, the z-score is 1.645 (you can find this value in a standard normal distribution table).
E = 1.645 \times \frac{18.8}{\sqrt{35}} \approx 5.41
Substituting the given values into the formula, we get:
Final Answer
Therefore, the correct answer choice is: - 235.4 < μ < 245.8
Need Help with Homework?
Stuck on a difficult problem? We've got you covered:
- Post your question or upload an image
- Get instant step-by-step solutions
- Learn from our AI and community of students