The frequency table solution for TI-83 and TI-84

Put the list of numbers in one list (let's say L1) and the frequencies in a separate list (for simplicity's, make it L2 in this example.) Under the STAT menu, in the CALC sub-menu, choose

2-Var Stats L1, L2

Assuming the frequencies are in the second list, the sum of the y values is n, the size of the sample and the sum of the xy is the sum of all the x values. You then need to divide (sum of xy)/(sum of y) to get the average x-bar.

As for the median, you have to do it by hand, just like the folks with the TI-30xIIs.

Here are the lists from class, the first number x and the second number f(x). The answers are in the comments.

This year's daily differences, 2015 - (avg. 1999-2014)
-9, 1
-8, 3
-7, 4
-6, 7
-5, 13
-4, 15
-3, 12
-2, 16
-1, 11
0, 24
1, 27
2, 24
3, 24
4, 25
5, 18
6, 14
7, 11
8, 8
9, 14
10, 5
11, 7
12, 1
13, 1
14, 4
15, 2
16, 3
17, 5
18, 4
20, 2
21, 1

Here is the list of wins by NFL teams in 2014

12, 5
11, 4
10, 3
9, 4
8, 2
7, 4
6, 3
5, 1
4, 2
3, 2
2, 2

Answers in the comments.