A Test of Writing Ability Is Given to a Random $\overline { \mathrm { d } }$

Multiple Choice

A test of writing ability is given to a random sample of students before and after they completed a formal writing course.The results are given below.Construct a 99% confidence interval for the mean difference between the before and after scores if $\overline { \mathrm { d } }$ (before - after) = 2.0 and sd =2.6457 $\text { Before } 70\quad80\quad92\quad99\quad93\quad97\quad76\quad63\quad68\quad71\quad74$ After 69 79 90 96 91 95 75 64 62 64 76

A) (-0.2,4.2)
B) (-0.1,4.1)
C) (-13.6,17.6)
D) (1.2,2.8)
E) (-0.5,4.5)