An article in Talanta (2005, Vol. 65, pp. 895€“899) presented a 2³factorial design to find lead level by using flame atomic absorption spectrometry (FAAS). The data are in the following table.

The factors and levels are in the following table.

(a) Construct a normal probability plot of the effect estimates. Which effects appear to be large?

(b) Conduct an analysis of variance to confirm your findings for part (a).

(c) Analyze the residuals from this experiment. Are there any problems with model adequacy?

Transcribed Image Text:

Lead Recovery (%) Factors Run ST pH RC R1 39.8 51.3 57.9 R2 42.1 48 58.1 85.9 84.2 78.9 78.9 84.2 94.4 84.2 90.9 94.7 105.3 I|I + + + + II + +I I + + EI +I +I + + -234 5678