A random sample of the closing stock prices in dollars for a company in a recent year is listed below. Assume that a is $1.91. Construct the 90% and 99% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. The 90% confidence interval is($____,$____) (Round to two decimal places as needed.) The 99% confidence interval is($____,$____) (Round to two decimal places as needed.)

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A random sample of the closing stock prices in dollars for a company in a recent year is listed below. Assume that a is $1.91. Construct the 90% and 99% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. The 90% confidence interval is($____,$____) (Round to two decimal places as needed.) The 99% confidence interval is($____,$____) (Round to two decimal places as needed.)
### Confidence Interval Calculation for Stock Prices

**Scenario:**
A random sample of the closing stock prices in dollars for a company in a recent year is listed below. Assume that the standard deviation (\(\sigma\)) is $1.91.

**Stock Prices:**
- 18.08
- 16.45
- 20.88
- 15.65
- 17.09
- 15.64
- 19.56
- 16.84
- 15.79
- 20.42
- 16.95
- 19.31
- 15.38
- 18.69
- 21.66
- 17.14

**Task:**
Construct the 90% and 99% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals.

**Explanation:**

- **90% Confidence Interval:** This interval gives the range within which you can be 90% confident that the true population mean lies. The width of this interval indicates the level of certainty about the mean.
  
- **99% Confidence Interval (Not Shown):** While this is not depicted in the image, constructing a 99% confidence interval would provide a wider range than the 90% interval, reflecting increased certainty (but less precision) about the mean.

**Interpretation:**
The 90% confidence interval shown on the image suggests a range that estimates where the true mean of the stock prices lies, with a confidence level of 90%. By comparing the widths of the 90% and 99% confidence intervals, one would notice that a higher confidence level (99%) results in a wider interval.

**Calculation Note:**
To find the specific numerical interval, the appropriate statistical methods and software would complete the calculations based on the given data and standard deviation.

This exercise demonstrates an important concept in statistics: the trade-off between the level of confidence and the precision of your estimate.
Transcribed Image Text:### Confidence Interval Calculation for Stock Prices **Scenario:** A random sample of the closing stock prices in dollars for a company in a recent year is listed below. Assume that the standard deviation (\(\sigma\)) is $1.91. **Stock Prices:** - 18.08 - 16.45 - 20.88 - 15.65 - 17.09 - 15.64 - 19.56 - 16.84 - 15.79 - 20.42 - 16.95 - 19.31 - 15.38 - 18.69 - 21.66 - 17.14 **Task:** Construct the 90% and 99% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. **Explanation:** - **90% Confidence Interval:** This interval gives the range within which you can be 90% confident that the true population mean lies. The width of this interval indicates the level of certainty about the mean. - **99% Confidence Interval (Not Shown):** While this is not depicted in the image, constructing a 99% confidence interval would provide a wider range than the 90% interval, reflecting increased certainty (but less precision) about the mean. **Interpretation:** The 90% confidence interval shown on the image suggests a range that estimates where the true mean of the stock prices lies, with a confidence level of 90%. By comparing the widths of the 90% and 99% confidence intervals, one would notice that a higher confidence level (99%) results in a wider interval. **Calculation Note:** To find the specific numerical interval, the appropriate statistical methods and software would complete the calculations based on the given data and standard deviation. This exercise demonstrates an important concept in statistics: the trade-off between the level of confidence and the precision of your estimate.
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18.08,15.79,16.45,20.42,20.88,15.65,17.09,15.38,15.64,19.56,16.84,16.95,19.31,18.69,21.66,17.14

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