Sampling Distribution 13A80A
1. **Problem Statement:**
Find the mean and variance of the sampling distribution of the mean. Given the population variance $\sigma^2 = 2$ and sample size $n = 169$, find the standard error of the mean.
2. **Formula and Explanation:**
- The mean of the sampling distribution of the sample mean is equal to the population mean $\mu$.
- The variance of the sampling distribution of the sample mean is given by:
$$\text{Var}(\bar{X}) = \frac{\sigma^2}{n}$$
- The standard error of the mean (SEM) is the standard deviation of the sampling distribution of the sample mean:
$$\text{SEM} = \sqrt{\text{Var}(\bar{X})} = \frac{\sigma}{\sqrt{n}}$$
3. **Calculations:**
- Given $\sigma^2 = 2$, so $\sigma = \sqrt{2}$.
- Sample size $n = 169$.
- Variance of sampling distribution:
$$\text{Var}(\bar{X}) = \frac{2}{169} = \frac{2}{169}$$
- Standard error of the mean:
$$\text{SEM} = \frac{\sqrt{2}}{\sqrt{169}} = \frac{\sqrt{2}}{13} = \frac{1.4142}{13} \approx 0.1088$$
4. **Interpretation:**
- The mean of the sampling distribution is the same as the population mean.
- The variance of the sampling distribution is smaller than the population variance by a factor of the sample size.
- The standard error quantifies the variability of the sample mean around the population mean.
**Final answer:**
- Mean of sampling distribution = $\mu$ (population mean)
- Variance of sampling distribution = $\frac{2}{169}$
- Standard error of mean = approximately $0.1088$