Calculate the standard error. May normality be assumed? (Round your answers to 4 decimal places.)

a) n = 27, = 0.24 Standard Error? Normality?

b) n = 56, = 0.43 Standard Error? Normality?

c) n = 123, = 0.47 Standard Error? Normality?

d) n = 578, = 0.004 Standard Error? Normality?