Example 12-1 Section
Click on the question mark for each question about the experiment to help un-pack clues toward understanding the appropriate design.
Effect of Hormones on Calcium Concentration in Birds
A study is conducted to evaluate the effect of a hormone treatment on plasma calcium concentration in male and female birds. Twenty birds (10 males and 10 females) were used for the study. Five birds of each gender were randomly assigned to either receive the hormone or act as a control. (no hormone). Plasma calcium concentration was measured at the end of the experiment in mg/100ml.
How many treatments are there?
How many levels of each treatment are there?
If there is more than 1 treatment, how are they related?
Crossed: each level of treatments occur with all levels of other treatments. (Factorial)
Nested: levels of a treatment are unique to different levels of another treatment.
Are treatments fixed or random effects?
Are there continuous covariates? (ANOCOVA)
What is the experimental unit?
An experimental unit is defined as that which recieves a treatment, (e.g., plant, person, plot of ground, petri dish, etc.).
Is there more than one experimental unit? (Split Plot)
How are treatment levels assigned to experimental units?
Completely at random? CRD
Restriction or randomization?
two-dimension: Latin Square
Are there sample units within experimental units? How many true replications are there?
Are there repeated measurements made on experimental units?