(7.1) Comment on the statement, 'a moving mean chart and a conventional mean

chart would be used with different types of processes'.

(7.2) The data in the table opposite shows the levels of contaminant in a chemical

product:

(a) Plot a histogram.

(b) Plot an individuals or run chart.

(c) Plot moving mean and moving range charts for grouped sample size

n = 4.

Interpret the results of these plots.

(7.3) In a batch manufacturing process the viscosity of the compound increases

during the reaction cycle and determines the end-point of the reaction.

Samples of the compound are taken throughout the whole period of the

reaction and sent to the laboratory for viscosity assessment. The laboratory

tests cannot be completed in less than three hours. The delay during testing

is a major source of under-utilization of both equipment and operators.

Records have been kept of the laboratory measurements of viscosity and the

Ammonia content Day Ammonia Temperature Operator (ppm) (C) 24.1 10 26.0 16 20.9 11 26.2 13 25.3 17 20.9 12 23.5 12 21.2 23.8 21.5 23.0 27.2 22.5 24.0 27.5 16 19.1 17 27.4 18 26.9 19 28.8 20 29.9 21 27.0 22 26.7 23 25.1 24 29.6 25 28.2 26 26.7 27 29.0 28 22.1 29 23.3 30 20.2 31 23.5 32 18.6 33 21.2 34 23.4 35 16.2 36 21.5 37 18.6 13 38 20.7 16 39 18.2 11 40 20.5 12 Use suitable techniques to detect and demonstrate changes in ammonia concentration?Levels of contamination in a chemical product Sample Result Sample Result (ppm) (ppm) 404.9 41 409.6 402.3 42 409.6 402.3 43 409.7 403.2 44 409.9 406.2 45 409.9 406.2 410.8 402.2 47 410.8 401.5 48 406.1 IE765 5E 3 0. J0 UAWNE 401.8 49 401.3 402.6 50 401.3 402.6 51 404.5 414.2 52 404.5 416.5 53 404.9 418.5 54 405.3 422.7 55 405.3 422.7 56 415.0 404.8 57 415.0 18 401.2 58 407.3 404.8 59 399.5 20 412.0 60 399.5 21 412.0 61 405.4 22 405.9 405.4 23 404.7 397.9 24 403.3 390.4 25 400.3 390.4 26 400.3 395.5 27 400.5 395.5 28 400.5 395.5 29 400.5 69 398.5 30 402.3 70 400.0 31 404.1 71 400.2 32 404.1 72 401.5 33 403.4 73 401.5 34 403.4 74 401.3 35 402.3 75 401.2 36 401.1 76 401.3 37 401.1 77 401.9 38 406.0 78 401.9 39 406.0 79 404.4 40 406.0 80 405.7Date and time Moving mean Moving mean viscosity .i'tln'er power 07,?04 07.30 1020 21 09.30 2250 27 11.30 3240 28 1 3.30 48 10 35 Batch completed and discharged 1 8.00 1230 22 21.00 2680 22 08,104 00.00 3'? 10 28 03.00 3980 33 06.00 5980 36 Batch completed and discharged 1 3.00 2240 22 1 6.00 3 3 20 30 1 9.00 3800 35 22.00 5040 31 Batch completed and discharged 09,104 04.00 15 10 25 07.00 2680 2'? 10.00 3240 28 1 3.00 4220 30 1 6.00 5410 3'? Batch completed and discharged 23.00 1 8 80 19 10,104 02.00 3410 24 05.00 4190 26 08.00 4990 32 Batch completed and discharged Standard error of the means viscosity 490 Standard error of the means stirrer power 90 Week Demand (Tn) Week Demand (Tn) 25 8 26 7.5 27 7 7 28 6.5 ONOU AWN- 8.5 29 10.5 8 30 9.5 8.5 31 8 10.5 32 10 8.5 33 8 11 34 4.5 7.5 35 10.5 9 36 8.5 6.5 37 9 6.5 38 7 6.5 39 7.5 40 10.5 17 6.5 41 10 9 42 7.5 9 43 11 8 44 5.5 21 7.5 45 9 22 6.5 46 5.5 23 47 9.5 24 48