statistics Questions?

Question

For the data values 45, 63, 28 and 39, find the mean of the sample means and the standard deviation of the sample means for all possible samples of size 3.

Answer 1

 

mean = 45 + 63 + 28 + 39 / 4 = 175 / 4 = 43.75

 

mean = 43.75

 

 

43.75 - 45 =  - 1.25   and (1.25)² = 1.5625

 

43.75 - 63 =  -19.25  and  (-19.25)² = 370.5625

 

43.75 - 28 =   15.75  and (15.75)²  = 248.0625

 

43.75 - 39 = 4.75  and (4.75)² = 22.5625

 

 

variance = 1.5625 + 370.5625 + 248.0625 + 22.5625  / 4 = 160.6875

 

S.D = sqrt (var) = sqrt (160.6875) =12.6763