Statistics 101: Section L - Laboratory 9
This lab consists of two group activities. For the first activity, you will design an experiment to
determine the optimal cooking time for a new brand of microwave popcorn. For the second
activity, you will design an experiment to determine the effectiveness of the Atkins diet.
For all activities, keep in mind the three principles of good experiments: control of outside
variables, randomization and replication within the experiment.
Activity 1: Imagine you are employed in the test kitchen of Company Z. Company Z is rolling out
a new brand of microwave popcorn. Your group must design an experiment to determine the
optimal cooking time for the new brand of microwave popcorn. The new popcorn will be sold in
individual packages, each with the same label weight. Your task is to design an experiment that
will produce data to help you make an informed decision as to the optimal cooking time for the new
brand of microwave popcorn.
a) First decide on a response. What aspect of the popcorn will help you decide on the optimal
cooking time? How will you measure your response? (Hint: Think about comparing the
response between the individual packages.) Be specific.
b) What are the experimental units for this study? (In other words, what are you conducting
the experiment on?)
c) What is the main factor for this experiment? How many levels of this factor will you
include in your experiment? What are these levels?
d) A secondary factor for this experiment is the wattage of the microwave. Explain how you
will incorporate two different wattage microwaves (700 watts and 1000 watts) into this
experiment.
e) What are the treatment combinations for your experiment?
f) Come up with a list of outside variables (variables other than the factors) that might affect
your response. How will you control for these variables in your study?
g) How will you incorporate replication in your study?
h) From a statistical point of view more replication is better, e.g. 100 experimental units for
each treatment combination. From a practical point of view why might you want less
replication, e.g. 10 experimental units in each treatment combination?
i) How will you incorporate randomization in your experiment? Be specific about how you
will randomize. From your description, I should be able to perform the randomization.
j) Draw a diagram of your experimental design.
Activity 2: There is considerable debate in the medical community about the benefits of the
“Atkins Diet.” This diet involves eating relatively large amounts of protein and fats and very few
carbohydrates. We would like to design an experiment to compare the weight loss achieved on the
Atkins diet with the weight loss achieved while on a diet based on the USDA food pyramid. There
are 100 people available for this experiment.
a) Who are the experimental units for this experiment? (In other words, who are we
conducting the experiment on?)
b) What is the response variable for this experiment? How will you measure it? Be specific.
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c) What is the factor for this experiment? How many levels does the factor have? What are
they?
d) How will you incorporate control in this experiment? What are some variables that could
influence the response? How will you control for these variables?
e) One important characteristic of our subjects that cannot be controlled for is gender.
Suppose out of the 100 people available for this experiment 60 are women and 40 are men.
We wish to block on gender. How will you incorporate replication in a block experiment?
f) How will you incorporate randomization in this experiment?
g) Draw a diagram of your block experimental design.
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Stat 101 L: Laboratory 9 – Answer Sheet
Names: _________________________
_________________________
_________________________
_________________________
Activity 1:
a) What is the response and how will you measure the response?
b) What are the experimental units?
c) What is the factor? How many levels? What are the levels?
d) How will you incorporate the second factor of two different wattage microwaves?
e) What are the treatments?
f) Outside factors that may affect the response and how you will control each one.
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g) How will you incorporate replication?
h) Practical reason for having less replication?
i) Describe how you will randomize so that I can perform the randomization by following
your description.
j) Diagram of the experiment.
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Activity 2:
a) What are the experimental units?
b) What is the response and how will you measure the response?
c) What is the factor? How many levels? What are the levels?
d) Outside factors that may affect the response and how you will control each one.
e) How will you incorporate replication in a block experiment?
f) Describe how you will randomize so that I can perform the randomization by following
your description.
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g) Diagram of the experiment.
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