Reaction Time Worksheet Calculate 'Measures of Center' Graphing

Reaction Time Worksheet
Question: Does your table group have a different reaction time than a table near you?
Measure: You and your partner’s reaction time following instructions on the screen.
Record: Your reaction time on the chart paper provided. When everyone at your table is
finished, transfer the data on the chart paper to your table below:
Observation
(person)
1
2
3
4
5
6
7
8
9
Sum of all
observations
Mean
(average)
Reaction time
(milliseconds) Your table
Reaction time (milliseconds)
Neighboring table
Number of people in your table group (number of observations): n=_________
Calculate ‘Measures of Center’
Definition: A ‘measure of center’ for a data set summarizes all of its values with a single
number. Examples are mean, median, and mode.
Calculate: Mean (or average) reaction time of your table group = Sum of all observations
(second to last row in table above) divided by the number of observations in your group (n)
Mean reaction time = __________________________
Next, choose a group near you and copy their Reaction Time data from their easel to
your table above (last column).
Graphing
Step 1: Draw bars on your graph paper to display the mean reaction times of your table and
the table near you (see example A below).
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Example A: Means
Question: What can you say about the reaction time data by looking at your
graph? Fill in the blanks below to make statements about your graph.
My group has an average reaction time of _______ milliseconds.
Their group has an average reaction time of _______ milliseconds.
My group’s average reaction time is (greater than / less than / the same as) their
group’s.
The difference between the average reaction time of my group and their group is
_______ milliseconds.
Graphing
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Step 2: Next, add your raw data to the bar graph by locating and drawing one dot for each
observation. Do the same for the data from the table next to you (see example B below).
Example B: Means with raw data
Question: What more can you say about the reaction time data by looking at your
graph with the raw data included? Fill in the blanks below to make statements
about your graph.
There are _____ observations in my group.
There are _____ observations in their group.
The highest value in my group was _______ milliseconds and the lowest value was
_______ milliseconds.
The highest value in their group was _______ milliseconds and the lowest value
was _______ milliseconds.
Calculating “Measures of Variability”
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Definition: A ‘measure of variability’ for a data set describes how its values vary
with a single number. Examples are range and mean absolute deviation (MAD).
Calculate: Range of reaction times observed at your table = the longest reaction time minus
the shortest reaction time.
Range from my table:
Longest reaction time – Shortest reaction time = _________________________
Range from the table group near you:
Longest reaction time – Shortest reaction time = _________________________
My group’s range is (wider / narrower) than their group’s range.
Calculate: Mean Absolute Deviations (MAD) of your table group = the average distance of
data points away from the mean.
Enter your group’s data in the table below:
Observation
1
2
3
4
5
6
7
8
Sum of all
deviations
Mean
(average)
A. Reaction Time B. Mean Reaction
(in milliseconds) Time
Leave blank
same as row 1
same as row 1
same as row 1
same as row 1
same as row 1
same as row 1
same as row 1
Leave blank
Leave blank
Leave blank
C. Deviation from the mean = A minus B
(make any negative #s positive)
MAD = sum of all deviations (second to last row above) divided by number of observations
My table’s MAD = ______________
MAD from the table near me (same table as earlier):_____________________
Graphing
Step 3: Draw lines on your bar graph to represent your MADs (see example C below).
→ The top line = mean reaction time + MAD
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→ The bottom line = mean reaction time - MAD
Example C: Means with raw data and mean absolute deviations (MADs)
Question: What more can you say about the reaction time data by looking at your graph
with the MAD values included? Choose the student whose statement best represents your
data and complete the sentence to explain your thinking below.
Student 1: One MAD range is much larger than the other.
Student 2: Both MAD ranges are very close to the mean.
Student 3: In relation to the full ranges of the MADs, there is quite a bit of overlap between
them.
Student 4: In relation to the full ranges of the MADs, there is not very much overlap
between them.
I agree with Student #____ because_________________________________________
_________________________________________________________________; this
makes me think ____________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
Now, do your best to answer the question:
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Does your table group have a different reaction time than the table near you?
How confident are you? Explain.
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_________________________________________________________________________
_____________________________________________
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