Question

Problem 2.187 Samples of a cast aluminum part are classifed on the basis of surface finish (in microinches) and edge finish. The results of 115 parts are summariaed as follows edge finish excellent good excelent 88 finish good 2 10 Let A denote the event that a sample has excellent surface finish, and let 8 denote probabilities. Round your answers to three decimal the event that a sample has excellent edge finish. If a part is selected at random, determine the following (a) PIA) 0808 (b) P(B)- 0.869 e PA) (d) PIAN8) e) PIAUB) PIA UB) Statistical Tables and Charts

Answer 1

(a)

	Edge finish excellent	Edge finish good	Total
Surface finish excellent	88	5	93
Surface finish good	12	10	22
Total	100	15	115

A = Surface finish excellent

B = Edge finish excellent

P(A)= 93/115 = 0.8087

(b)

P(B) = 100/115 = 0.8696

(c)

P(A') = 1 - P(A) = 0.1913

(d)

(e)

(f)

= 0.1913 + 0.8696 - (12/115)

= 1.0609 - 0.1043 =  0.9566