Based on many years of experience, a lecturer in ECON241 has determined that the probability distribution function of X, the number of students absent in the Tuesday morning lecture, is as follows:
![1164_Compute the expected value of X.png](https://secure.tutorsglobe.com/CMSImages/1164_Compute%20the%20expected%20value%20of%20X.png)
1. Find the probability that on a given Tuesday either 20, 30 or 40 students will be absent.
2. Find the probability that on a given Tuesday more than 30 students will be absent.
3. Compute the expected value of X
4. Compute the variance of X
5. Compute the expected value of Y = 7X+30
6. Compute the variance of Y = 7X+30