The TIRE Company researcher wants to determine if her new type of tire wears better than the current tire types. She selected three existing types to be evaluated with her newly developed tire. She had four tire types, all of the same size. She had available four cars and four drivers which could be used during the driving test. The test was to measure the tread wear during a 25,000 mile driving test. Describe how you would design an appropriate experiment for her. Describe in detail the treatment structure and the design structure. Write down the appropriate model and key out the corresponding analysis of variance table; include sources and degrees of freedom.
4.3 A food scientist wants to develop a healthy yet eatable muffin by changing some of the
ingredients. He has three main factors to vary, OIL at three levels, SUGAR at two levels, and
EGG WHITE POWDER at four levels. In order to have a reference point, he compared the
experimental muffins to a STANDARD muffin recipe. He has a pan in which he can bake 25
muffins at a time. Design an experiment for him, describe the design and treatment
structures, write down an appropriate model, and key out the corresponding analysis of
4.6 A researcher wants to set up a study to evaluate four methods of teachiang statistics. One
possible design would be to teach one class of students with each of the teaching methods
and use the students in the class as replications of the teaching method. Discuss the
implications of using this design.
5.2 The effects of two chemical treatments and two irrigation levels on the growth of two
cultivars of wheat was studied using eight growth chambers. Each growth chamber was
assigned a level of irrigation and a cultivar. There were eight pots in each growth
chamber, thus the two levels of chemical were randomly assigned to the pots, denoted by
Chem 1 or Chem 2, for a total of 4 pots for each chemical within an irrigation*cultivar
combination. The randomization scheme is displayed in the following table.