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.

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 46 410.8 402.2 410.8 401.5 406.1 401.8 401.3 402.6 401.3 402.6 404.5 414.2 404.5 416.5 404.9 418.5 405.3 422.7 405.3 422.7 415.0 404.8 415.0 401.2 407.3 404.8 399.5 412.0 399.5 412.0 405.4 405.9 405.4 404.7 397.9 403.3 390.4 400.3 390.4 400.3 395.5 400.5 395.5 400.5 395.5 400.5 398.5 402.3 400.0 31 404.1 400.2 32 404.1 401.5 33 403.4 401.5 34 403.4 401.3 35 402.3 401.2 36 401.1 401.3 37 401.1 401.9 38 406.0 78 401.9 39 406.0 404.4 40 406.0 80 405.7