The estimated times and immediate predecessors for the activities in a project at Howard$$ Umrah's retinal scanning company are given in the following table. Assume that the activity times are independent.

$$

Time $($weeks$)$

Immediate

Time $($weeks$)$

Immediate

Activity

a

m

b

$$Predecessor$($s$)$

Activity

a

m

b

$$Predecessor$($s$)$

A

C

A

B

D

B

This exercise contains only parts$$ a$,$ b$,$ c$,$ d$,$ and e$.$

Part $2$

$$a$)$ Based on the activity time$$ estimates, the expected times and variance for each of the activities are $($round your response to two decimal$$ places$)$: