A desk manufacturer claims that the average time it takes to assemble a desk is 90 minutes with a standard deviation of 32 minutes. Suppose a random sample of 64 desk buyers is taken and time to assemble recorded. The standard deviation of the sample mean is ______ minutes.

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Answer:

The standard deviation of the sample mean is 4 minutes

Step-by-step explanation:

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]s = \frac{\sigma}{\sqrt{n}}[/tex].

For a skewed variable, the Central Limit Theorem can also be applied, as long as n is at least 30.

In this problem, we have that:

The standard deviation of the population is 32.

Sample of 64.

So

[tex]s = \frac{32}{\sqrt{64}} = 4[/tex]

The standard deviation of the sample mean is 4 minutes