Having done poorly on a particular exam in a junior high school, 24 students decide to write the exam again to try and improve their mark. Results are given in the following table.

Student	n	Average	Standard deviation
Attempt 1 (A1)	24	51	3.4
Attempt 2 (A2)	24	55	4.7
Difference (d = A1 - A2)	24	-4.0	2.6

(a) Find a 95% confidence interval for the difference in mean scores between attempt 1 and attempt 2. (Round your answers to 4 decimal places, if needed.) (b) Based on this confidence interval, can we conclude there is a difference in mean scores between attempt 1 and attempt 2?