# Week 2. Expected value of a function - 2nd example

Link to the classroom item I am referring to: https://www.coursera.org/learn/machine-learning-probability-and-statistics/lecture/6uZiQ/expected-value-of-a-function

Description:

I think I’m missing something really simple here. Can anyone explain me how the wins are calculated here in the second example of the video? If a person in paying 5\$ to start playing and then receives 2 times the value of the dice, then doesn’t it has to be the following?

• Roll: 1 → (2 · 1) - 5 = -3
• Roll: 2 → (2 · 2) - 5 = -1
• Roll: 3 → (2 · 3) - 5 = 1
• Roll: 4 → (2 · 4) - 5 = 3
• Roll: 5 → (2 · 5) - 5 = 5
• Roll: 6 → (2 · 6) - 5 = 7

So then the expected value of the example function is: 2

2 Likes

Sorry for the delay. Do you need help with this question?

Can anyone explain ?? I am having the same doubt!!!

Yes I need the help!!!

You are correct, that’s a glaring error in the video.

I’ll submit a ticket to see if it can be fixed.

@JP_X, thanks for this post. My head was spinning trying to make sense of this topic in the video.