AFDA – Unit 9: Statistics and Surveys
Day 3 Notes: Experimental Design
Name: _________________
Block: _____ Date:_______
Today we will learn about experimental design.
Experimental design involves a very meticulous procedure for ________________
the environment surrounding _______ variables.
________________ group – the group that will ________________ being studied.
________________ group – the group that receives ______ treatment.
___________________ - each group should be selected by using a random process.
Ex: Assign numbers and use a random number generator
________________ – a ________________ treatment
_______________________ – the power of the human mind to affect positive results
without treatment.
______________________- An experimental design where the subjects or the
evaluators do not know who is in which group.
________________ blind – when the person administering the ________________ or
placebo knows which group gets what but the subjects do not know.
________________ blind – when both the ______________ and the ____________
do not know who is in which group.
________________ - the ability to ________________ the experiment to help verify or
deny the claim.
____________ - the arranging of experimental units into groups with _____________
factors to help eliminate a lurking variable.
Ex: Separating subjects into male and female before selecting a control group
and a treatment group.
**Experimental design seeks to establish a CAUSAL (cause/effect) relationships
between two variables.
Experimental design includes ____________________, _____________________,
_________________________, and ______________________________________ .
Examples:
1. A researcher is studying the correlation between caffeine consumption and school
performance. The researcher groups students into male and female. The
researcher then picks 30 random boys and 30 random girls. Students’ caffeine
consumption is tracked over 9 weeks and their grades are compared.
a) Is this an example of an experiment? Why or why not?
b) What types of techniques are used to eliminate bias?
c) What could the researcher add to the design to make this a better study?
2. A researcher is studying the correlation between eating an apple a day and doctor
visits. The researcher hires another person who randomly selects participants using
a random number generator. The first half is instructed to eat an apple a day and
the second half is instructed to not eat any apples. The researcher tracks all
participants for a period of two years to see how many doctor visits each patient
makes.
a) Is this an example of an experiment? Why or why not?
b) What types of techniques are used to eliminate bias?
c) What could the researcher add to the design to make this a better study?
3. A researcher is studying the correlation between a specific weight loss pill and the
presence of obesity. The researcher randomly selects patients who suffer from
obesity he then puts them in groups according to their gender. The researcher then
randomly determines which patients will take the medication and which patients
take a placebo pill. The researcher tracks the weight loss of each patient in each
gender over a period of 9 mo.
a) Is this an example of an experiment? Why or why not?
b) What types of techniques are used to eliminate bias?
c) What could the researcher add to the design to make this a better study?