Question

	Depth	of bore
edge condition	Above target	Below target
coarse	15	10
moderate	21	24
smooth	49	81

The data from 200 machined parts are summarized as follows:

(a) What is the probability that a part selected has a moderate edge condition and a below-target bore depth?
Round your answer to two decimal places (e.g. 98.76).

P=

(b) What is the probability that a part selected has a moderate edge condition or a below-target bore depth?
Round your answer to two decimal places (e.g. 98.76).

P=

(c) What is the probability that a part selected does not have a moderate edge condition or does not have a below-target bore depth?
Round your answer to two decimal places (e.g. 98.76).

P=

Answer 1

	Depth	of bore
edge condition	Above target	Below target	total
coarse	15	10	25
moderate	21	24	45
smooth	49	81	130
total	85	115	200

a)

P(moderate edge and below target bore  condition) = 24/200=0.12

b)

probability ( a part selected has a moderate edge condition or a below-target bore depth) = [ n(moderate)+n(below) - n(moderate and below) ] / n(total) = (45+115-24)/200=0.68

c)

probability ( a part selected does not have a moderate edge condition or does not have a below-target bore depth)=

=1 - P(a part selected has a moderate edge condition or a below-target bore depth) = 1-0.68 = 0.32