deggust, a play on the verb “degust”, is to savour the edibble designs to fully appreciate it
Take-away message 3
The edibble system and its (future) extensions signficiantly reframe the way that the experimental designs are constructed from standard, often recipe-driven, approach
I refer this programming language agnostic system to as “The Grammar of Experimental Designs”
A work-in-progress book “The Grammar of Experimental Designs” can be found at
Giesbrecht, Francis G. and Gumpertz, Marcia L. (2004) Planning, Construction, and Statistical Analysis of Comparative Experiments.
Bailey, Rosemary (2008) Design of Comparative Experiments.
Lawson, John (2015) Design and Analysis of Experiments with R.
STORY 1🌱 The folklore of fervent field experiments
STORY 1 🌱 The folklore of fervent field experiments
Consider a field experiment in agriculture where plot are laid in out as 6 rows by 8 columns (each also called strip). There are 4 modes of seedbed preparation and 3 crop varieties that are of the interest to the researcher. The mode of seedbed preparation is assigned randomly to the whole columns, and the crop variety is assigned randomly to the whole row. This experimental design is called a strip-plot design.
STORY 1 🌱 The folklore of fervent field experiments
Consider a field experiment in agriculture where plot are laid in out as 6 rows by 8 columns (each also called strip). There are 4 modes of seedbed preparation and 3 crop varieties that are of the interest to the researcher. The mode of seedbed preparation is assigned randomly to the whole columns, and the crop variety is assigned randomly to the whole row. If fertility gradients are suspected then the strips can be grouped into sets (i.e. introduce blocking factors in one or more directions). This variation is called a strip-block design.
A manufacturer of household appliances wants to find the best combination of wash temperature and drying temperature to produce unwrinkled cotton sheets at the end of the laundry session. He wants to compare four different wash temperatures and three different drying temperatures. He uses eight similar washing machines and six similar dryers. First, 48 cotton sheets are randomly allocated to the washing machines, six per machine. The wash temperatures are randomly allocated to the washing machines so that two machines are run at each temperature. After the wash, the six sheets in each machine are randomly allocated to the dryers, one per dryer. Then the drying temperatures are randomly allocated to the dryers so that two machines are run at each temperature. After the drying, all 48 sheets are scored by experts for how wrinkled they are.
Records are intended variables, e.g. responses, that will be measured or observed
You can set expectations of the record (plausible values) and simulate records, censoring values (default as missing) outside of expectations, or export data with data validation
Recipes for chocolate and orange cookies include exactly the same ingredients up to the point where the syrup was added to the batch. However, after the cookies were baked, the chocolate cookies had an appealing round and plump appearance, while the orange cookies spread during the baking process and became thin, flat, and unappealing. A factorial experiment was devised to determine if there was a way to change the process of making the orange cookies that would reduce the spreading during baking. The factors that were chosen to be varied were A: the amount of shortening in the dough batch (80% of what the recipe called for or 100%), B: the baking temperature (below, at, or above the temperature called for by the recipe), and C: the temperature of the cookie sheet upon which the cookies were placed to be baked (hot out of the oven, or cooled to room temperature). The cookie-making process consists of the two steps: 1. mix cookie dough batch, and 2. bake cookies. Factor A is related to step 1, factors B and C to step 2. The amount of shortening was a hard-to-vary factor because each time it was changed it required making a new batch of cookie dough, while the baking temperature and tray temperature were easy to vary. Once a batch of dough was made, there was enough to make six trays of cookies, and all six combinations of baking temperature and tray temperature could be tested within each dough batch. First, plan to make four batches of cookie dough and randomly assign two batches to use 80% of the recipe recommended amount of shortening and two batches to receive the full amount of shortening recommended by the recipe. Next, bake six trays of cookies from each batch of dough and completely randomize the six combinations of bake temperature and tray temperature to the six trays of cookies within each batch.
