Question 1192283
a. mean is 12, sd is sqrt(8)/2 or sqrt(2)
b. mean 72.12, sd is sqrt(12)/8 or sqrt(3)/4

variance in pop is 8, so variance in sample is 8/4 or 2 and the sd is sqrt(2)
variance in pop is 12, so variance in sample of size 64 is 12/64 and sd is 2 sqrt(3)/8 or sqrt(3)/4.