7 A normally distributed population has a mean of 70 and a s

7. A normally distributed population has a mean of 70 and a standard deviation of 9. a. What is the mean of the distribution of sample means for this population? (2 pts.) b. What is the standard error of the distribution of sample means for n = 25?

Solution

A normal population has mean 70 and std dev = 9

Sample means follow a normal distirbution with mean same as 70

and std dev = 9/root n

Hence x bar is normal with (70, 9/rt n) where n is the sample size

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b) When n =25

STd error = 9/rt 25 = 9/5 = 1.80