2)We have a population with mean 5.7 years and standard deviation 0.7 years.
When we have a sampling distribution (distribution of the sample means) for a sample with size n, its mean and standard deviation will be:
The mean of the sampling distribution will be equal to the population mean, but the standard deviation will be affected by the sample size.
For a sample size n = 55 and a population standard deviation of 0.7 years we can calculate the sampling distribution standard deviation as:
Answer: the sampling distribution standard deviation is 0.09 years.