Homework SourseLet X denote the waiting time in seconds for a large databas
Let X denote the waiting time in seconds for a large database update to complete.
The probability mass function for X is:
Find the follwing:
A) f(X).
B) P(X<0.35)
C) P(0.25<=x<3.45)
D) E(x)
| x | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 |
|---|---|---|---|---|---|---|
| f(x) | 0.2 | 0.1 | 0.3 | 0.4 | 0.1 | 0.2 |
Solution
X: Waiting time in seconds
The table below gives all the values
| x | 0.1 | 0.2 | 0.3 | 0.4 | 0.5 | 0.6 | |
| f(x) | 0.2 | 0.1 | 0.3 | 0.4 | 0.1 | 0.2 | |
| xf(x) | 0.02 | 0.02 | 0.09 | 0.16 | 0.05 | 0.12 | 0.46 |
| Cum F(x) | 0.2 | 0.3 | 0.6 | 1 | 1.1 | 1.2 | |
| P(X<0.35) | F(0.3) | 0.6 | |||||
| C) P(0.25<=x<3.45) | F(0.6)-F(0.2) | 0.9 | |||||
| d) E(x) | 0.46 |
