The Sandbox Task
Andrew and Ivy are organizing the lab. Andrew leaves his pen in a pile of papers
here (location 1) and then goes to get a coffee
X
Location 1
While Andrew is out of the room, Ivy takes his pen and places
it in the papers here (location 2).
X
X
Location 1
Location 2
While Andrew is out of the room, Ivy takes his pen and places it in the
papers here (location 2)
X
Location 1
X
My Answer
X
Location 2
Measuring Your Bias Score
• The General Concept
• Measure the distance from your answer to
location 1 (in mm). This measurement will
indicate your bias.
• This measurement will either have a positive
or negative sign associated with it
• The following slides will help you determine if your measurement is
positive or negative
Measuring Your Bias Score
Possible Responses
• If your response is towards location 2 and away from location 1, your
answer is positive
Positive Bias
Where will Andrew look for his pen when he gets back?
+10mm
X
Location 1
X
My Answer
X
Location 2
Measuring Your Bias Score
Possible Responses
• If your response is towards location 2 and away from location 1 and
overshoots location 2, your answer is positive
Positive Bias
Where will Andrew look for his pen when he gets back?
+25mm
X
Location 1
X
X
Location 2 My Answer
• Possible Responses
• If your response is away from location 1 and away from location 2,
your answer is negative
Negative Bias
Where will Andrew look for his pen when he gets back?
-1mm
X X
X
Location 1
My Answer
Location 2
No Bias
Possible Responses
• If your response is at the exact same spot as location 1, your answer
is 0
No Bias
Where will Andrew look for his pen when he gets back?
0 mm
X
Location 1
My Answer
X
Location 2
• The following slides will help you determine the magnitude of your
bias (the distance between your answer and the correct location).
Bias Calculation
• In order to calculate the bias score you will have to perform a few
measurements and some simple subtraction
Bias Calculation Example 1
15mm
X
Location 1
X
My Answer
X
Location 2
Bias Calculation Example 1
15mm
5mm
X
Location 1
X
My Answer
X
Location 2
Bias Calculation Example 1
15mm
Unknown
5mm
X
Location 1
X
My Answer
X
Location 2
Bias Calculation Example 1
15mm
15-5=Unknown
Unknown
5mm
X
Location 1
X
My Answer
X
Location 2
Bias Calculation Example 2
15mm
X
Location 2
X
X
Location 1
My Answer
Bias Calculation Example 2
15mm
12mm
X
Location 2
X
My Answer
X
Location 1
Bias Calculation Example 2
15mm
Unknown
12mm
X
Location 2
X
My Answer
X
Location 1
Bias Calculation Example 2
15mm
Unknown
15-12 = unknown
12mm
X
Location 2
X
My Answer
X
Location 1