Ciis questIOIT Deluw If n=24, (x-bar)=30, and s=7, construct a confidence interval at a 98% confidence level. Assume the data came from a normally distributed population. Give your answers to one decimal place.

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### Constructing a Confidence Interval

Given the problem:

- Sample size (\( n \)) = 24
- Sample mean (\( \bar{x} \)) = 30
- Sample standard deviation (\( s \)) = 7

We are asked to construct a confidence interval at a 98% confidence level, assuming the data comes from a normally distributed population.

### Solution Steps:

1. **Identify the Parameters:**
   - We need to calculate the confidence interval for the mean (\( \mu \)).

2. **Determine the Appropriate Formula:**

   Since the population standard deviation is unknown and \( n < 30 \), we use the t-distribution:

   \[
   \bar{x} \pm t \left(\frac{s}{\sqrt{n}}\right)
   \]

   Where:
   - \( t \) is the t-score that corresponds to the desired confidence level and degrees of freedom (\( df = n-1 \)).

3. **Calculate the t-score:**

   Look up the t-score for a 98% confidence level and 23 degrees of freedom.

4. **Calculate the Margin of Error:**

   \[
   t \left(\frac{7}{\sqrt{24}}\right)
   \]

5. **Construct the Confidence Interval:**

   Place the result into:
   \[
   30 \pm \text{Margin of Error}
   \]

### Diagrams or Graphs:

The image contains several handwritten notes and calculations, primarily numbers and operations, possibly relating to the determination of the degrees of freedom or critical t-value. However, there are no explicit graphs or diagrams detailing the calculations further.

---

This transcription can be used for educational purposes to understand how to calculate a confidence interval using sample means, sample sizes, and the t-distribution.
Transcribed Image Text:### Constructing a Confidence Interval Given the problem: - Sample size (\( n \)) = 24 - Sample mean (\( \bar{x} \)) = 30 - Sample standard deviation (\( s \)) = 7 We are asked to construct a confidence interval at a 98% confidence level, assuming the data comes from a normally distributed population. ### Solution Steps: 1. **Identify the Parameters:** - We need to calculate the confidence interval for the mean (\( \mu \)). 2. **Determine the Appropriate Formula:** Since the population standard deviation is unknown and \( n < 30 \), we use the t-distribution: \[ \bar{x} \pm t \left(\frac{s}{\sqrt{n}}\right) \] Where: - \( t \) is the t-score that corresponds to the desired confidence level and degrees of freedom (\( df = n-1 \)). 3. **Calculate the t-score:** Look up the t-score for a 98% confidence level and 23 degrees of freedom. 4. **Calculate the Margin of Error:** \[ t \left(\frac{7}{\sqrt{24}}\right) \] 5. **Construct the Confidence Interval:** Place the result into: \[ 30 \pm \text{Margin of Error} \] ### Diagrams or Graphs: The image contains several handwritten notes and calculations, primarily numbers and operations, possibly relating to the determination of the degrees of freedom or critical t-value. However, there are no explicit graphs or diagrams detailing the calculations further. --- This transcription can be used for educational purposes to understand how to calculate a confidence interval using sample means, sample sizes, and the t-distribution.
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