If it rains tomorrow the probabliity is .8 that John will practice his piano lesson. IF it does not rain tomor?
If it rains tomorrow is probabliity. John 8, who practices the piano lesson. If not rain tomorrow, just one. 4 chance that John practice. Suppose that the probability of rain tomorrow is 60%. What is the piani John probablility practice their lessons?
rain and practice ==> (.60)(.80) = .48
no rain and practice ==> (.40)(.40) = .16
add these to get: .64
there is a probability of .64 that John will practice
***
as a check:
rain and no practice: (.60)(.20) = .12
no rain and no practice (.40)(.60) = .24
.12 + .24 = .36 = P(no practice)
P(practice) + P(no practice) = .64 + .36 = 1 yep, it works
it is 0.2……
coz 1-0.8 = 0.2
R=Rains tomorrow
N=doesn’t rain tomorrow
L= practice piano lesson
P(L/R)=0.8
P(L/N)=0.4
P(R)=0.60
P(R’)=0.40
P(L)=(0.60)(0.80) +(0.40)(0.40) = 0.48+0.16=0.64