Eight soldiers visit a shooting range on two consecutive days and fire 100 shots in the range. On the first day their scores were 57, 64, 49, 72, 66, 68, 75 and 60. On the second day, their corresponding scores were 60, 70, 54, 76, 60, 65, 80 and 60. Examine whether their performance has improved on the second day after practice. Test at 5% level of significance.
Level of significance