The table shows the results of a 5-point musical aptitude test given to a group of first-grade students. (a) Find the average aptitude score. (b) Find the median aptitude score. \begin{tabular}{|l|c|c|c|c|c|c|} \hline \begin{tabular}{l} Aptitude \\ score \end{tabular} & 0 & 1 & 2 & 3 & 4 & 5 \\ \hline Frequency & 7 & 15 & 18 & 20 & 11 & 9 \\ \hline \end{tabular} (a) The average aptitude score is $\square$ pôints. (Type an integer or a decimal.)

Step 1 ：To find the average aptitude score, we need to multiply each score by its frequency and sum those products.

Step 2 ：The products are: \(0 \times 7 = 0\), \(1 \times 15 = 15\), \(2 \times 18 = 36\), \(3 \times 20 = 60\), \(4 \times 11 = 44\), \(5 \times 9 = 45\).

Step 3 ：The sum of the products is \(0 + 15 + 36 + 60 + 44 + 45 = 200\).

Step 4 ：The total number of students is \(7 + 15 + 18 + 20 + 11 + 9 = 80\).

Step 5 ：The average aptitude score is the sum of the products divided by the total number of students: \(200 \div 80 = 2.5\).

Step 6 ：The final answer is \(\boxed{2.5}\) points.