Question

Given the summary of the two classes of sicknesss (Yes, No):

Probability of "Yes" = 40%  

Probability of "No" = 60%

The following summary shows the frequency of each class for a given feature/attribute

"fever" that can be "high" and "low".

  

	high	low	total
yes	400	300
No	200	100
Total

a. Calculate the all the number of yes class

b. Calculate the all the records of no class.

c. Calculate the all high fever records

d. calculate all the low fever records.

e.  How many total records are there.

f. What is the posterior probability of Yes given high fever?

g. What is the probability of No given low fever?

h:  If Bill shows high fever, is he sick or not sick?

Answer 1

a) all the number of yes class =400+300=700

b)  all the records of no class=200+100=300

c) all high fever records=400+200=600

d) all the low fever records. =300+100=400

e) total records are ther =400+200+300+100=1000

f) posterior probability of Yes given high fever =400/600=2/3

g)  probability of No given low fever =100/400=1/4

h)

the probability of being sick is 2/3 ; but we can not say it for certain if he is  sick or not sick