Listed below are speeds (mi/h) measured from traffic on a busy highway. This simple random sample was obtained at 3:30 P.M. on a weekday. Use the sample data to construct a 95% confidence interval estimate of the population standard deviation. 64 63 63 57 63 53 59 58 59 70 61 69

MATLAB: An Introduction with Applications
6th Edition
ISBN:9781119256830
Author:Amos Gilat
Publisher:Amos Gilat
Chapter1: Starting With Matlab
Section: Chapter Questions
Problem 1P
icon
Related questions
Topic Video
Question
### Constructing a Confidence Interval for Population Standard Deviation

**Problem Statement:**
Listed below are speeds (mi/h) measured from traffic on a busy highway. This simple random sample was obtained at 3:30 P.M. on a weekday. Use the sample data to construct a 95% confidence interval estimate of the population standard deviation.

**Traffic Speeds:**
```
64, 63, 63, 57, 63, 53, 59, 58, 59, 70, 61, 69
```

**Steps to Construct the Confidence Interval:**

1. **Calculate the Sample Mean & Standard Deviation:** 
   - First, you need to find the mean (average) of the sample data.
   - Then, calculate the standard deviation of the sample.

2. **Find the Chi-Square Critical Values:**
   - Access the chi-square distribution table to find the critical values for chi-square at the 95% confidence level, based on the sample size (n-1 degrees of freedom).

3. **Compute the Confidence Interval Estimate for the Population Standard Deviation:**

   The formula to calculate the confidence interval for the standard deviation \( \sigma \) is:
   \[
   \sqrt{\frac{(n-1)s^2}{\chi^2_{upper}}} < \sigma < \sqrt{\frac{(n-1)s^2}{\chi^2_{lower}}}
   \]
   where:
   - \( n \) is the sample size.
   - \( s \) is the standard deviation of the sample.
   - \( \chi^2_{upper} \) and \( \chi^2_{lower} \) are the critical values from the chi-square distribution table for the upper and lower bounds, respectively.

4. **Apply the Calculations:**
   - Plug in the values obtained into the formula above to get the confidence interval estimate.

**Interactive Table:**
- Click the icon to view the table of Chi-Square critical values. This will help you find the necessary chi-square values for your calculations.

**Final Output:**
- The confidence interval estimate is:
  \[
  \text{[Minimum Value]} \text{ mi/h} < \sigma < \text{[Maximum Value]} \text{mi/h}
  \]
 
Ensure to round the final results to one decimal place as needed.

Teaching Tip
Transcribed Image Text:### Constructing a Confidence Interval for Population Standard Deviation **Problem Statement:** Listed below are speeds (mi/h) measured from traffic on a busy highway. This simple random sample was obtained at 3:30 P.M. on a weekday. Use the sample data to construct a 95% confidence interval estimate of the population standard deviation. **Traffic Speeds:** ``` 64, 63, 63, 57, 63, 53, 59, 58, 59, 70, 61, 69 ``` **Steps to Construct the Confidence Interval:** 1. **Calculate the Sample Mean & Standard Deviation:** - First, you need to find the mean (average) of the sample data. - Then, calculate the standard deviation of the sample. 2. **Find the Chi-Square Critical Values:** - Access the chi-square distribution table to find the critical values for chi-square at the 95% confidence level, based on the sample size (n-1 degrees of freedom). 3. **Compute the Confidence Interval Estimate for the Population Standard Deviation:** The formula to calculate the confidence interval for the standard deviation \( \sigma \) is: \[ \sqrt{\frac{(n-1)s^2}{\chi^2_{upper}}} < \sigma < \sqrt{\frac{(n-1)s^2}{\chi^2_{lower}}} \] where: - \( n \) is the sample size. - \( s \) is the standard deviation of the sample. - \( \chi^2_{upper} \) and \( \chi^2_{lower} \) are the critical values from the chi-square distribution table for the upper and lower bounds, respectively. 4. **Apply the Calculations:** - Plug in the values obtained into the formula above to get the confidence interval estimate. **Interactive Table:** - Click the icon to view the table of Chi-Square critical values. This will help you find the necessary chi-square values for your calculations. **Final Output:** - The confidence interval estimate is: \[ \text{[Minimum Value]} \text{ mi/h} < \sigma < \text{[Maximum Value]} \text{mi/h} \] Ensure to round the final results to one decimal place as needed. Teaching Tip
Expert Solution
trending now

Trending now

This is a popular solution!

steps

Step by step

Solved in 3 steps with 3 images

Blurred answer
Knowledge Booster
Hypothesis Tests and Confidence Intervals for Means
Learn more about
Need a deep-dive on the concept behind this application? Look no further. Learn more about this topic, statistics and related others by exploring similar questions and additional content below.
Similar questions
Recommended textbooks for you
MATLAB: An Introduction with Applications
MATLAB: An Introduction with Applications
Statistics
ISBN:
9781119256830
Author:
Amos Gilat
Publisher:
John Wiley & Sons Inc
Probability and Statistics for Engineering and th…
Probability and Statistics for Engineering and th…
Statistics
ISBN:
9781305251809
Author:
Jay L. Devore
Publisher:
Cengage Learning
Statistics for The Behavioral Sciences (MindTap C…
Statistics for The Behavioral Sciences (MindTap C…
Statistics
ISBN:
9781305504912
Author:
Frederick J Gravetter, Larry B. Wallnau
Publisher:
Cengage Learning
Elementary Statistics: Picturing the World (7th E…
Elementary Statistics: Picturing the World (7th E…
Statistics
ISBN:
9780134683416
Author:
Ron Larson, Betsy Farber
Publisher:
PEARSON
The Basic Practice of Statistics
The Basic Practice of Statistics
Statistics
ISBN:
9781319042578
Author:
David S. Moore, William I. Notz, Michael A. Fligner
Publisher:
W. H. Freeman
Introduction to the Practice of Statistics
Introduction to the Practice of Statistics
Statistics
ISBN:
9781319013387
Author:
David S. Moore, George P. McCabe, Bruce A. Craig
Publisher:
W. H. Freeman