Quality control

TECH 4433 Quality Control Abdulrahman Alsharari___________________________ Chapter 3 Homework Answer Sheet (2 pts each)

3.8 (a) average = __130_____________

standard deviation = ___8.914____________

(b) To make the graph we need to know the class , which we can find as √𝑛 Which is approx. 6 and width is (116-118)/6 = 7 and then we will make the frequency distribution.

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(c) 11| 8 9 12|0 1 1 2 3 3 4 4 4 4 5 5 5 5 5 6 7 8 8 9 9 9 13|0 1 1 1 3 3 6 7 7 14|0 0 1 2 2 15|1

16|0

(d) median = ___128____________

Q1 = ___124____________

Q3 = __135.25_____________

3.22

0.000

20.000

40.000

60.000

80.000

100.000

120.000

140.000

0 5 10 15 20 25 30 35 40 45

Chart Title

3.26

3.29 (a) P(x = 1) = __0.0196_____________

(b) P(x > 1) = __0.0198_____________

(c) P(x > 1) = __0.00995_____________

3.33 (a) P(x < 1) = __0.1175_____________

(b) Here the profit per sale is $25 but due to warranty another $50 dollar would be spent for the calculators that would be replaced due to warranty. Therefore the expected profit per calculator here could be computed as: = 25 - 0.1175*50 = 19.1248 Therefore 19.1248 is the expected profit per customer here.

3.34 P(x < 12) = __0.125_____________

3.35 P(x > 1) = __22.22%_____________

3.40 (a) P(x=3) = __0.15__________________

(b) u = ___7_________________

(c) P(x=10) = __0.0890_________________

3.43 (a) P(acceptance) = ___0.6333_________________

(b) P(acceptance) = ____0.6591________________

____Its not satisfactory________________________________

(c) ____if the lot size was 150 , the 5 would be small enough fraction what we could use the approximation and its satisfactory_______________________________ 3.46 P(x >1) = ___0.0952____________

3.50 (a) P(x=51) = _0.986_________________

3.51 (a) P(x < 35) = __0.1587_________________

# that fail = _7935 products__________________

(b) P(x > 48) = ___0.0548________________

# that exceed = __2740 products_________________