Question

An experiment is to be carried out to determine the optimal combination of microwave oven
settings for microwave popcorn. Cooking time has three possible settings (3,4, and 5 minutes)
and cooking power has two settings (low power, high power). The response (to be minimized)
is the number of burned plus the number of unpopped kernels.

a. Identify the experimental unit.
b. Identify the experimental factor(s), levels, and any factor-level combinations if present

Answer 1

a. In statistical experiment an experimental unit is that entity to which you apply your combination of experimental factors or treatments. Here experimental unit is popcorn kernels say a bowl of popcorn kernels that is put in the microwave.

b. Experimental factors are those variables which affect the response variable of the experiment. In this experiment the time setting and cooking power are the two variables which affects the response i.e. the number of burned plus the number of unpopped kernels.

Levels are the different values of factor we use in an experiment. Time factor has 3 levels : 3, 4 or 5 minutes. Cooking power has 2 levels: low or high.

A combination of factor and level is called a treatment. Here there are 6 factor-level combination or treatments:

• 3 minutes on Low power
• 3 minutes on High power
• 4 minutes on Low power
• 4 minutes on High power
• 5 minutes on Low power
• 5 minutes on High power