Enter the data into a list by pressing "Stat" and then pressing "Enter" to select "1:Edit." Under the Edit menu, move the cursor under L1, L2, L3 or whichever list you want to use; type in the first number and then press "Enter." Repeat until all numbers have been entered.
Press the yellow "2ND" button and then press "Stat." A menu appears. Move over with the right arrow until "Math" is highlighted on the top row. Scroll down with the down arrow key until "4:Median" is highlighted. Press "Enter."
Enter your desired list by pressing the yellow "2ND" button and then press the number corresponding to the list you wish to use --- 1 brings up L1, 2 brings L2, 3 brings L3 and so on. Close the parentheses and press "Enter."