A random sample of 18 venture-capital investments in a certain business sector yielded the accompanying data, in millions of dollars. Assuming that the population standard deviation is $1.78 million, a 95% confidence interval for the mean amount, µ, of all venture-capital investments in this business sector is from $5.65 million to $7.30 million. Conditions for computing the confidence interval are satisfied. Complete parts (a) through (d) below. (Note: The sum of the data is $116.52 million and the mean is $6.47 million.) Click here to view the investment data. Click here to view page 1 of the table of areas under the standard normal curve, Click here to view page 2 of the table of areas under the standard normal curve, a. Find a 90% confidence interval for u. The 90% confidence interval is from $ million to $ million. Investment data (Round to two decimal places as needed.) 5.93 6.83 6.46 9.67 3.17 5.39 5.98 5.64 3.85 8.73 6.44 7.16 4.25 8.09 8.81 5.20 8.27 6.65

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# Confidence Interval Calculation for Venture-Capital Investments

A random sample of 18 venture-capital investments in a certain business sector yielded data in millions of dollars. Assuming that the population standard deviation is $1.78 million, a 95% confidence interval for the mean amount, µ, of all venture-capital investments in this sector is from $5.65 million to $7.30 million. Conditions for computing the confidence interval are satisfied.

### Investment Data
The data is presented in a matrix with three rows and six columns:

- Row 1: 5.93, 6.83, 6.46, 9.67, 3.17, 5.39
- Row 2: 5.98, 5.64, 3.85, 8.73, 6.44, 7.16
- Row 3: 4.25, 8.09, 8.81, 5.20, 8.27, 6.65

Total sum of the data is $116.52 million, and the mean is $6.47 million.

### Task

a. Find a 90% confidence interval for µ.

The 90% confidence interval is from $ ___ million to $ ___ million.
(Round to two decimal places as needed.)

### Additional Resources
- [Table of areas under the standard normal curve - Page 1](#)
- [Table of areas under the standard normal curve - Page 2](#) 

This exercise helps in understanding the application of statistical methods to real-world financial data, essential for making informed investment decisions.
Transcribed Image Text:# Confidence Interval Calculation for Venture-Capital Investments A random sample of 18 venture-capital investments in a certain business sector yielded data in millions of dollars. Assuming that the population standard deviation is $1.78 million, a 95% confidence interval for the mean amount, µ, of all venture-capital investments in this sector is from $5.65 million to $7.30 million. Conditions for computing the confidence interval are satisfied. ### Investment Data The data is presented in a matrix with three rows and six columns: - Row 1: 5.93, 6.83, 6.46, 9.67, 3.17, 5.39 - Row 2: 5.98, 5.64, 3.85, 8.73, 6.44, 7.16 - Row 3: 4.25, 8.09, 8.81, 5.20, 8.27, 6.65 Total sum of the data is $116.52 million, and the mean is $6.47 million. ### Task a. Find a 90% confidence interval for µ. The 90% confidence interval is from $ ___ million to $ ___ million. (Round to two decimal places as needed.) ### Additional Resources - [Table of areas under the standard normal curve - Page 1](#) - [Table of areas under the standard normal curve - Page 2](#) This exercise helps in understanding the application of statistical methods to real-world financial data, essential for making informed investment decisions.
**Transcription: Educational Website Content**

**b. Why is the confidence interval you found in part (a) shorter than the 95% confidence interval?**

The [Value] used in computing the confidence interval found in part (a) is [less than] the corresponding value for the 95% confidence interval.

**c. Draw a graph to display both confidence intervals. Choose the correct graph below.**

- **Option A:** Displays a 95% CI for µ above a wider interval with a 90% CI for µ below a narrower interval on a number line ranging from 4 to 7, with 5.5 marked as the central point.

- **Option B:** Displays a 95% CI for µ as a wider interval and a 90% CI for µ as a narrower interval directly below it on a number line ranging from 4 to 7, with 5.5 as the central point. (Selected Option)

- **Option C:** Displays a 90% CI for µ above and a 95% CI for µ below with inversion compared to Option A on a number line ranging from 4 to 7.

- **Option D:** Displays a 90% CI for µ as a wider interval and a 95% CI for µ as a narrower interval below it on a number line ranging from 4 to 7.

**d. Which confidence interval yields a more accurate estimate of µ? Explain your answer.**

[The 95% CI] yields a more accurate estimate of µ, since [it provides a higher level of confidence].
Transcribed Image Text:**Transcription: Educational Website Content** **b. Why is the confidence interval you found in part (a) shorter than the 95% confidence interval?** The [Value] used in computing the confidence interval found in part (a) is [less than] the corresponding value for the 95% confidence interval. **c. Draw a graph to display both confidence intervals. Choose the correct graph below.** - **Option A:** Displays a 95% CI for µ above a wider interval with a 90% CI for µ below a narrower interval on a number line ranging from 4 to 7, with 5.5 marked as the central point. - **Option B:** Displays a 95% CI for µ as a wider interval and a 90% CI for µ as a narrower interval directly below it on a number line ranging from 4 to 7, with 5.5 as the central point. (Selected Option) - **Option C:** Displays a 90% CI for µ above and a 95% CI for µ below with inversion compared to Option A on a number line ranging from 4 to 7. - **Option D:** Displays a 90% CI for µ as a wider interval and a 95% CI for µ as a narrower interval below it on a number line ranging from 4 to 7. **d. Which confidence interval yields a more accurate estimate of µ? Explain your answer.** [The 95% CI] yields a more accurate estimate of µ, since [it provides a higher level of confidence].
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