If a population has a standard deviation of 28 units what is

If a population has a standard deviation of 28 units, what is the standard error of the mean if samples of : (6 points)

a. size 18 are selected?

b. size 44 are selected?

c. size 76 are selected?

d. As sample size increases, what happens to the standard error of the mean?

PLEASE SHOW WORK

Solution

a)
Standard Error= sd/ Sqrt(n)
Where,
sd = Standard Deviation
n = Sample Size

Standard deviation( sd )=28
Sample Size(n)=18
Standard Error = ( 28/ Sqrt ( 18) )
= 6.6

b)

Sample Size(n)=44
Standard Error = ( 28/ Sqrt ( 44) )
= 4.221

c)
Standard deviation( sd )=28
Sample Size(n)=76
Standard Error = ( 28/ Sqrt ( 76) )
= 3.212

d)
It decreased