Use the antimony data discussed in this week’s lesson. You can find the data at the book web site as a plain text file and as an Excel and CSV spreadsheet. Run a two-way ANOVA including interaction and use this model for all the following questions even if you decide the interaction term is expendable. Additional procedures may also be needed to fully answer the following questions.
Important: The antimony data are available in two formats:
• Standard statistical/database format for data, where each row is an observation.
• Table form, in which each column is a different cooling method, each row is a specific level of antimony, and the values in the table are the measured strengths. There are three observations for each combination of antimony and cooling method.
Excel needs to use the table format. StatCrunch needs to use the database format. The worksheet tabs indicate the format. The data are also available in non-Excel format (text and CSV).
(a) Does the level of antimony affect joint strength?
(b) Does the type of cooling affect joint strength?
(c) Does there seem to be a problem with interaction here?
(d) Explain in words what interaction would mean in terms of this study and these variables. Give an example.
(e) Do the assumptions for ANOVA seem to be met here? Why or why not?
