Evaluation of flexography printing plates. Refer to the Journal of Graphic Engineering and Design (Vol. 3, 2012) study of the quality of flexography printing, Exercise 9.24 (p. 544). Recall that four different exposure times were studiedâ€”8, 10, 12, and 14 minutesâ€”and that the measure of print quality used was dot area (hundreds of dots per square millimeter). Tukeyâ€™s multiple comparisons procedure (at an experimentwise error rate of .05) was used to rank the mean dot areas of the four exposure times. The results are summarized below. Which exposure time yields the highest mean dot area? Lowest?
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Evaluation of flexography printing plates. Flexography is a printing process used in the packaging industry. The process is popular, since it is cost-effective and can be used to print on a variety of surfaces (e.g., paperboard, foil, and plastic). A study was conducted to determine if flexography exposure time has an impact on the quality of the printing (Journal of Graphic Engineering and Design, Vol. 3, 2012). Four different exposure times were studied: 8, 10, 12, and 14 minutes. A sample of 36 print images were collected at each exposure time level, for a total of 144 print images. The measure of print quality used was dot area (hundreds of dots per square millimeter). The data were subjected to an analysis of variance, with partial results shown in the accompanying table.
a. Compute the missing entries in the ANOVA table.
b. Is there sufficient evidence to indicate that mean dot area differs depending on the exposure time? Use Â = .05