symmetric distribution. A random sample of size 16 has sample mean 10 and sample standard deviation 2. (a) Check Requirements Is it appropriate to use a Student's i distribution to compute a confidence interval for the population mean u? Explain. (b) Find a 90% confidence interval for μ. (c) Interpretation Explain the meaning of the confidence interval you computed.

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### Basic Computation: Confidence Interval

Suppose \( x \) has a mound-shaped symmetric distribution. A random sample of size 16 has a sample mean of 10 and a sample standard deviation of 2.

1. **Check Requirements**
   - **Question**: Is it appropriate to use a Student’s t distribution to compute a confidence interval for the population mean \( \mu \)? Explain.
   - **Answer**: Yes, it is appropriate to use a Student’s t distribution because the sample size is small (n < 30) and the population is assumed to have a symmetric distribution. The Student’s t distribution is used instead of the normal distribution under these conditions.

2. **Find a 90% confidence interval for \( \mu \)**:
   - To find a 90% confidence interval for the population mean \( \mu \), use the formula:
     \[
     \bar{x} \pm t_{\alpha/2} \left( \frac{s}{\sqrt{n}} \right)
     \]
     Where:
     - \( \bar{x} \) is the sample mean (10),
     - \( t_{\alpha/2} \) is the t-value for a 90% confidence level with \( n-1 \) degrees of freedom (df = 15),
     - \( s \) is the sample standard deviation (2),
     - \( n \) is the sample size (16).

3. **Interpretation**
   - **Question**: Explain the meaning of the confidence interval you computed.
   - **Answer**: The 90% confidence interval provides a range of values that, with 90% confidence, contains the true population mean \( \mu \). This means that if we were to take many random samples of size 16 and construct a confidence interval from each sample, approximately 90% of those intervals would contain the true population mean.

By using these steps, you can understand how to determine and interpret a 90% confidence interval for a population mean using a sample's data.
Transcribed Image Text:### Basic Computation: Confidence Interval Suppose \( x \) has a mound-shaped symmetric distribution. A random sample of size 16 has a sample mean of 10 and a sample standard deviation of 2. 1. **Check Requirements** - **Question**: Is it appropriate to use a Student’s t distribution to compute a confidence interval for the population mean \( \mu \)? Explain. - **Answer**: Yes, it is appropriate to use a Student’s t distribution because the sample size is small (n < 30) and the population is assumed to have a symmetric distribution. The Student’s t distribution is used instead of the normal distribution under these conditions. 2. **Find a 90% confidence interval for \( \mu \)**: - To find a 90% confidence interval for the population mean \( \mu \), use the formula: \[ \bar{x} \pm t_{\alpha/2} \left( \frac{s}{\sqrt{n}} \right) \] Where: - \( \bar{x} \) is the sample mean (10), - \( t_{\alpha/2} \) is the t-value for a 90% confidence level with \( n-1 \) degrees of freedom (df = 15), - \( s \) is the sample standard deviation (2), - \( n \) is the sample size (16). 3. **Interpretation** - **Question**: Explain the meaning of the confidence interval you computed. - **Answer**: The 90% confidence interval provides a range of values that, with 90% confidence, contains the true population mean \( \mu \). This means that if we were to take many random samples of size 16 and construct a confidence interval from each sample, approximately 90% of those intervals would contain the true population mean. By using these steps, you can understand how to determine and interpret a 90% confidence interval for a population mean using a sample's data.
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