A population has a mean [tex]$\mu=132$[/tex] and a standard deviation [tex]$\sigma=23$[/tex]. Find the mean and standard deviation of the sampling distribution of sample means with sample size [tex][tex]$n=57$[/tex][/tex].

The mean is [tex]$\mu_{\bar{x}}=$ \square[/tex], and the standard deviation is [tex][tex]$\sigma_{\bar{x}}=$[/tex] \square[/tex] (Round to three decimal places as needed.)



Answer :

To find the mean and standard deviation of the sampling distribution of sample means, we need to apply the concepts from the Central Limit Theorem.

### Step 1: Mean of the Sampling Distribution of Sample Means

The mean of the sampling distribution of sample means (denoted as [tex]\(\mu_{\bar{x}}\)[/tex]) is the same as the population mean [tex]\(\mu\)[/tex]. Therefore,

[tex]\[ \mu_{\bar{x}} = \mu \][/tex]

Given that the population mean [tex]\(\mu = 132\)[/tex],

[tex]\[ \mu_{\bar{x}} = 132 \][/tex]

So, the mean of the sampling distribution of sample means is [tex]\(\mu_{\bar{x}} = 132\)[/tex].

### Step 2: Standard Deviation of the Sampling Distribution of Sample Means

The standard deviation of the sampling distribution of sample means is known as the standard error (denoted as [tex]\(\sigma_{\bar{x}}\)[/tex]). It can be calculated using the formula:

[tex]\[ \sigma_{\bar{x}} = \frac{\sigma}{\sqrt{n}} \][/tex]

Here, [tex]\(\sigma\)[/tex] is the population standard deviation, and [tex]\(n\)[/tex] is the sample size. Given [tex]\(\sigma = 23\)[/tex] and [tex]\(n = 57\)[/tex],

[tex]\[ \sigma_{\bar{x}} = \frac{23}{\sqrt{57}} \][/tex]

### Step 3: Calculate and Round the Standard Error

First, compute the square root of [tex]\(57\)[/tex]:

[tex]\[ \sqrt{57} \approx 7.550 \][/tex]

Next, divide the population standard deviation by this value:

[tex]\[ \sigma_{\bar{x}} = \frac{23}{7.550} \approx 3.046 \][/tex]

Rounding to three decimal places, the standard error is [tex]\(\sigma_{\bar{x}} \approx 3.046\)[/tex].

### Final Answer

[tex]\[ \mu_{\bar{x}} = 132 \][/tex]

[tex]\[ \sigma_{\bar{x}} = 3.046 \][/tex]

Therefore, the mean of the sampling distribution of sample means is [tex]\(\mu_{\bar{x}} = 132\)[/tex], and the standard deviation is [tex]\(\sigma_{\bar{x}} = 3.046\)[/tex].