Psyc 393 Spring 2013
Lab Exercise #2 – Stroop Test
Due at end of lab period
Resources Needed:





Your CogLab e-registration code
A Pharos Print Card (available from the Library)
The CogLab manual (PDF on the class website)
GraphPad Prism, available under CSUSM site license for Mac OS X and Windows from
http://graphpad.com/paasl/index.cfm?sitecode=csusm
Microsoft Word (or another document editor)
Scoring - Your lab will be graded on:
 Writing that is clear, organized, free from grammar & spelling errors, and clearly answers the questions.
 Quality of graphs – graphs should be formatted, meet the requirements, and labeled and titled
 On time – late papers will be accepted, but with substantial penalty
Create your CogLab Account
After you’ve purchased your CogLab access code - Follow the instructions at
http://coglab.wadsworth.com/Information/HTMLData/20130127125825480509000.html
You will be assigned a CogLab ID and choose a password - be sure to remember them as you will need them for other
labs this semester.
Run the CogLab experiment: Stroop Effect
Go to http://coglab.wadsworth.com/
Click “Stroop Effect” in the “Attention” block
Carefully read and understand the introduction, and the instructions.
Log in with your CogLab information (ID/Password: not the same as your CSUSM ID!)
You should see “Access Approved” in green.
Click “Start experiment” when you are ready to begin.
Once you are finished, answer YES to add your data to the global pool of data.
Exercise 1: Data Collection and Entry into Prism
Goal – enter your individual data into a Prism sheet for later analysis.
 View your individual data in CogLab by clicking the “You can also view your own data” link.
 Open Prism
 Create a new Table & Graph – Important – what type of data sheet?
 There are 45 trials to enter. However, you need to split the data into two columns, based on the Independent
Variable (IV). What is the IV?
Write a one paragraph statement describing the research design, the IV and DV, and how you determine (for each data
sample row) what the IV is for that row?
Once you have your data entered, copy & paste the spreadsheet from Prism into Word.
Exercise 2A: Univariate Analyses – Histogram, Mean(SD)










First, verify with the instructor or GA that your data has been entered properly before you proceed!
In Prism, select your data table (it will be called “Data 1” by default)
Click the “=” icon (Analyze)
Choose “Column Analyses / Frequency Distribution”
Select Only one column (Column A only)
Click OK, and again OK on the next screen (leave all Parameters as defaults)
Find your histrogram (it will be in “Graphs” named “Histogram of Data 1”)
Clean up your graph (label the X and Y axes, add a descriptive Title, etc.)
Copy & Paste into your Word.doc, and add a Legend / Caption (e.g. “Graph X : blah blah”)
Repeat for your 2nd column of data
Exercise 2B : Multivariate Analyses : T-test and Scatterplot-with-Jitter for your individual data set.
 T-Test
o In Prism, select your data table (it will be called “Data 1” by default)
o Click the “=” icon (Analyze)
o Choose “Column Analyses / t-tests”
o Select Both columns (A and B)
o Which T-test to choose? Paired? Unpaired?
o Also click “Output: Create a table of descriptive stats for each column”
o Write a textual description of the T-test results, as if you were writing a “Results” section. Include the
N, mean (SD) of group data, the effect size, and the P-value and whether it was statistically significant.
 Scatterplot with Jitter
o In Prism, select your data table (it will be called “Data 1” by default)
o Click the “Graphs” folder
o Select the first graph style (Scatter Plot, Vertical)
o Plot : Mean with SD (rather than SEM)
o Clean the graph, and add to your word document
Exercise 3A, 3B – Repeat 2A and 2B using the grouped data (the data file will be provided by the instructor during
the lab period)
Exercise 4 – Discussion
Write a brief (1-2 paragraph) summary of what you found – did the results support Stroop’s hypothesis? (Be sure to
clearly restate Stroop’s hypothesis). Were your individual results consistent with the group results or did they differ
somehow? Given your individual experience, what are some potential issues or confounds with the methods used in
class?
Turning In: Please use the following header on page 1:
FirstName LastName
CogLab ID: (your coglab id)
Psyc 393 Lab #2 – Stroop Test
Date: (today’s date)
Checklist – your assignment should have:
 Your Name and CogLab ID#
 Exercise 1 - A data table with your individual data (2 columns, 30 rows and 15 rows)
 Exercise 1 – A 1-2 paragraph answer to the question
 Exercise 2A – Two graphs (histrograms), one for each column of data
 Exercise 2B – One paragraph Results Section description of the T-test results, one graph (Vertical Scatterplot)
showing both variables.
 Exercise 3A, 3B – same as 2A, 2B
 Exercise 4 – One or more paragraph answer to the questions