The compressive strength of concrete is normally distributed with mu = 2500 psi and sigma = 50 psi. A random sample of n = 8 specimens is collected. What is the standard error of the sample mean? Round your final answer to three decimal places (e.g. 12.345). The standard error of the sample mean is [ ]psi.

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Answer:

[tex]X \sim N(2500,50)[/tex]  

Where [tex]\mu=2500[/tex] and [tex]\sigma=50[/tex]

We select a sample size of n =8. Since the distribution for X is normal then we know that the distribution for the sample mean [tex]\bar X[/tex] is given by:

[tex]\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})[/tex]

And the standard error would be:

[tex]SE = \frac{50}{\sqrt{8}}= 17.678 psi[/tex]

Step-by-step explanation:

Previous concepts

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

Solution to the problem

Let X the random variable that represent the compressive strength of concrete of a population, and for this case we know the distribution for X is given by:

[tex]X \sim N(2500,50)[/tex]  

Where [tex]\mu=2500[/tex] and [tex]\sigma=50[/tex]

We select a sample size of n =8. Since the distribution for X is normal then we know that the distribution for the sample mean [tex]\bar X[/tex] is given by:

[tex]\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})[/tex]

And the standard error would be:

[tex]SE = \frac{50}{\sqrt{8}}= 17.678 psi[/tex]

Using the Central Limit Theorem, it is found that the standard error of the sample mean is of 17.678 psi.

The Central Limit Theorem states that for a sample of size n in a population with standard deviation [tex]\sigma[/tex], the standard error of the sample mean is given by:

[tex]s = \frac{\sigma}{\sqrt{n}}[/tex]

In this problem, we are given that [tex]\sigma = 50, n = 8[/tex]. Thus, the standard error of the sample mean is of:

[tex]s = \frac{\sigma}{\sqrt{n}} = \frac{50}{\sqrt{8}} = 17.678[/tex]

The standard error of the sample mean is of 17.678 psi.

A similar problem is given at https://brainly.com/question/22934264