Authentic Learning Task (ALT) #5: Back to the Block

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ALT #5: Back to the Block

Overview

In this ALT, you and your team continue to practice the twelve basic steps of Design of Experiments (DOE) by conducting and analyzing a second fractional factorial Jenga Block experiment.

Again, your team brainstorms and chooses three non-interacting factors and two levels for each factor to be tested via the L4 array. You stack the Jenga Blocks until the tower tumbles over. Again, the goal is to maximize the height of the tower.

The major difference between this ALT and ALT #4 is that you will be replicating (carefully repeating under the same controlled conditions) each of the runs in the L4 in order to get an estimate of random error. You are then able to perform an ANOVA to determine which factors are truly significant and at what significance level.

After completing this ALT, you should be able to demonstrate the following competencies:

  • Use sound sampling techniques and data analysis to make repeatable, defensible inferences (Comp. 1).
  • Solve real world problems by designing and conducting factorial experiments (Comp. 2).
  • Graphically display outcomes using simple graphical presentation methods (Comp. 3).
  • Use ANOVA to interpret experimental results (Comp. 4).

Materials and Equipment
No materials or equipment are needed to complete this ALT.

Safety and Disposal
No special safety or disposal procedures are required.

Pre-Activity

In this ALT, you repeat the Fractional Factorial Design of Experiment (with three factors) using Jenga Blocks but with replication of the trials. To prepare, you work through the example problem provided in the Participant Journal using Excel

Design of Experiments –Fractional Factorial with replication
This example is a replicated example that looks at the effects of combining the effects of different fertilizers, corn hybrids and the amount of water as part of a study to maximize the bushel yields of corn. By replicating, we mean repeating the trials.

Click here to access the example.
Click here to download its solution.

Additional Information on How to Conduct a Factorial and Fractional Factorial Experiments

NIST Section 5.3.3.4

Statsoft online textbook

Java Applets

Self Assessment
An experiment has been carried out to determine the effect of three factors on increasing the viscosity (centipoise) of the materials during mixing. The three factors are mixing speed (rpm), mixing time (minutes) and the viscosity of the materials before mixing (centipoises). A fractional factorial experiment has been carried out to determine the best settings.

Click here for the solution.

Activity

In your team, perform the following step to complete the activity:

  1. With your team, brainstorm to identify the factors and levels you wish to test.
  2. Refer to and review Instruction Sheet: Back to the Block.
  3. Have your facilitator approve your team's factor and level selections.
  4. Be sure that you understand of the ANOVA method and can properly use the Fisher Table for "trip values." Ask your facilitator if you need further clarification or assistance.

Post-Activity

Your team should now post its results from the activity to the Discussion Board.

Assignment
To prepare for ALT #6: Back to the Block Again, read pages 65-73 in your Statistical Experiments Participant Journal, and review ANOVA sites highlighted in the Pre-Activity section for the
next ALT.

Assessment
Your facilitator may use Assessment Sheet: Back to the Block to evaluate your results from the activity and your posting to the Discussion Board.
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