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To use a random-number table or random-number generator to obtain a sample (with replacement) of four digits between $0$and $9$.

Let, the given value:
$n=4$
Using the random number table, produce four digits between $0$and $9$. In the random number table, the first four digits in row $15$ are chosen as follows:
$0,7,8,5$
The sum of all values divided by the number of values can be used to compute the mean.
$\stackrel{¯}{\mathrm{x}}=\frac{0+7+8+5}{4}$

$=\frac{20}{4}$

$=5$

Repeat the previous exercise $50$times with different rows and columns, or use a random number generator to get the desired results.

As a result, depending on the first number chosen, the solutions may differ.

To find the mean and standard deviation of all possible sample means for samples of size $4$.

Let, the given value:

$n=4$

$=\frac{45}{10}$

$=4.5$

$=\sqrt{\frac{82.5}{10}}$

$≈2.8733$

As a result, the mean and standard deviation are $4.5$ and $2.8733$.

To calculate approximately the mean and standard deviation of the $50$ sample means that obtained in part (a).

The sample mean is the same as the population mean because the mean of the distribution is sampling.
The mean is determined as:
${\mathrm{μ}}_{\stackrel{¯}{x}}=\mathrm{μ}$

$=4.5$

And the standard deviation is determined as:

${\mathrm{σ}}_{\stackrel{¯}{x}}=\frac{\mathrm{σ}}{\sqrt{n}}$

$=\frac{2.8733}{\sqrt{4}}$

$≈1.4367$

As a result, the mean and standard deviation for sample size $50$ are $4.5$and $1.4367$.

To determine the mean and standard deviation of the $50$ sample means that obtained in part (a).

Determine the standard deviation as follows:

$\stackrel{¯}{x}=\frac{5+4.75+3.75+….+4.25+3.75+4.5}{50}$

$=4.54$

$≈1.4596$

Depending on the first number chosen, the solutions may differ.

To compare your answers in parts (c) and (d). And determine that how they different.

Since,the parts (c) and (d) have the most significant differences due to sampling error.
To be more specific, even though the numbers are fairly near to the expected values, various samples will have different means and standard deviations.