# Question

The following study is from Oehlert (2000). Dental fillings made from gold can vary in hardness depending on how the metal is treated prior to its placement in the tooth. Two factors thought to influence the hardness are the gold alloy and the condensation method. In addition, some dentists performing the dental work are better at some types of filling than others. Five dentists were randomly selected and agreed to participate in the experiment. Each dentist prepared 24 fillings (in random order), one for each of the combinations of condensation method (three levels) and type of alloy (eight levels). The levels of condensation and type of alloy are the only levels of interest to the researchers. The fillings were then measured for hardness using the Diamond Pyramid Hardness Number (big scores are better). The data are contained in the following table:

a. Write an appropriate linear statistical model for this experiment. Identify all the terms in your model, and state all the conditions that are imposed on these terms.

b. Display a complete analysis of variance table, including expected mean squares, F tests, and p-values.

c. Is there significant evidence of an interaction between condensation method and type of alloy?

a. Write an appropriate linear statistical model for this experiment. Identify all the terms in your model, and state all the conditions that are imposed on these terms.

b. Display a complete analysis of variance table, including expected mean squares, F tests, and p-values.

c. Is there significant evidence of an interaction between condensation method and type of alloy?

## Answer to relevant Questions

Refer to Exercise 17.35. a. Group the types of alloys such that alloys within a group have similar mean hardness scores. b. Group the types of condensation methods such that alloys within a group have similar mean hardness ...Refer to Exercise 17.5. a. Write down the expected mean squares. b. Run an analysis of variance and test for a significant analyst effect. c. Estimate the variance components associated with analysts, subjects, and error. ...There are many running shoes on the market of varying degrees of quality. Long-distance runners require a shoe that provides a significant reduction in impact shock compared to the standard running shoe intended for weekend ...An experiment is to be designed as a completely randomized design with a split-plot treatment assignment. Suppose the wholeplot treatment A has four levels. The split-plot treatments consist of the cross of two factors: ...Gasoline efficiency ratings were obtained on a random sample of 12 automobiles, 6 each of two different models. These ratings were taken at five different times for each of the 12 automobiles. a. Compute the mean efficiency ...Post your question

0