I'm going to do this on paint and upload it.
Hope this helps
The probability of rolling any specific number is 1/6. The expected number of points is found from:
E(points) = (1/6 * -1) + (1/6 * -2) + (1/6 * -3) + (1/6 * 4) + (1/6 * 5) + (1/6 * 6)
= 9/6 = 1.5 points
7, to find the mean add up all the numbers and then subtract by the amount of Humber a you added.
For example, 1,3,8,10 added together is 22. We added four numbers together, so divide by 4. The mean of 1,3,8,10 is 5.5