The estimated standard error for a sample of n = 9 scores with ss = 288 is 2. Among your choices, it should be B; s2 = 36 and sM = 2.
Hope that helps!
Step-by-step explanation:
You can also solve for d instead.
C, because you need to change them to the same fractions, 4/8 and 5/8.
Double them and you get 8/16 and 10/16, in the middle being 9/16.