A random sample of n 15 scores is selected from a populatio

A random sample of n = 15 scores is selected from a population. Based on this information alone, do I know that the distribution of samples means will be normal? Why or why not?

A random sample of n = 39 scores is selected from a population. Based on this information alone, do I know that the distribution of means will be normal? Why or why not?

. All samples of size n = 49 are selected from a population with ? = 60 with ? = 18. What is the average of the sample means?

Solution

A random sample of n = 15 scores is selected from a population. Based on this information alone, do I know that the distribution of samples means will be normal? Why or why not?

Since the sample size is less than 30, we can not conclude that the distribution of samples means will be normal

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A random sample of n = 39 scores is selected from a population. Based on this information alone, do I know that the distribution of means will be normal? Why or why not?

Since the sample size is larger than 30, based on Central Limit Theorem, we can conclude that the distribution of samples means will be normal

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. All samples of size n = 49 are selected from a population with ? = 60 with ? = 18. What is the average of the sample means?

sample mean=60 (stay the same)