Statistics 101: Section L - Laboratory 9
This lab consists of three 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 the
third activity, you will design an experiment to determine the average weight of one M&M.
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 line of microwave popcorns. Your group must design an experiment to determine the
optimal cooking time for one of the new brands of microwave popcorn in this new line. 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 groups 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 in
each treatment group. From a practical point of view why might you have less replication,
e.g. 10 experimental units in each treatment group?
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?
conducting the experiment on?)
(In other words, who are we
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b) What is the response variable for this experiment? How will you measure it? Be specific.
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.
Activity 3: In a previous lab, we conducted an observational study by selecting Fun Size bags of
M&Ms, weighing the bags and counting the number of M&Ms in each bag. From the analysis of
those data, we found that using least squares regression to predict the weight of an empty bag and
the average weight of a single M&M was not very successful. Part of the problem was that we
used data obtained from bags that contained 15 – 25 M&Ms in each bag, and then tried to use these
data to extrapolate back to the origin.
Your task in this activity is to design and conduct an experiment to obtain reasonable estimates of
the average weight of an empty Ziploc bag and the average weight of a single peanut M&M using
least squares regression. You will have a Tupperware container of peanut M&Ms, a Ziploc bag,
and a scale to conduct the experiment. You will put M&Ms in the bag and weigh the bag with the
M&Ms on the scale.
a) What is the response variable for this experiment?
b) What is the factor for the experiment? What levels of this factor will you use for this
experiment?
c) What are the “treatment” groups for this experiment?
d) What are the experimental units for this experiment?
e) What are some outside variables that may affect the response? How will these be controlled
in your experiment?
f) How will you incorporate replication in your experiment? How much replication will you
have?
g) How will you incorporate randomization in your experiment? Be specific about how you
will randomize when conducting the experiment. Create a data collection table in JMP
showing the treatments and the randomization you would use and submit a copy of the table
with the lab.
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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.
g) How will you incorporate replication?
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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.
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?
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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.
g) Diagram of the experiment.
Activity 3:
a) What is the response variable?
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b) What is the factor for the experiment? What levels of this factor will you use for this
experiment?
c) What are the “treatment” groups for this experiment?
d) What are the experimental units for this experiment?
e) What are some outside variables that may affect the response? How will these be controlled
in your experiment?
f) How will you incorporate replication in your experiment? How much replication will you
have?
g) How will you incorporate randomization in your experiment? Be specific about how you
will randomize when conducting the experiment. Create a data collection table in JMP
showing the treatments and the randomization you would use and submit a copy of the table
with the lab.
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