Lab 5: Mirror Tracing SPSS Lab
Created for SPSS v29.0.2.0 by Grant L. Saba
Introduction
This SPSS lab will require you to complete an online mirror tracing activity and add your data to the dataset supplied in the .sav file attached to this week’s modules. You can click here Links to an external site. to begin the mirror tracing activity, though you should read the instructions below before you begin.
Steps to complete the mirror tracing activity:
Make sure that you are using a computer with a mouse or a touchpad/trackpad as you
complete this activity.
Choose the square, then click “Submit.”
Complete both trials (non-mirrored and mirrored) and record your times. As frustrating as it might be, do your best to complete the shape, even if the outline is drastically different.
Repeat this two more times, until you have completed six attempts with the square.
SPSS Lab Learning Objectives
By the time you complete this SPSS lab, you will be able to…
…input new data and create new variables.
…conduct a repeated-measures ANOVA.
SPSS Lab Desсrіption
After completing trials in the mirror tracing activity, you can look at the gallery (also linked here Links to an external site.), where you can view the results of different people’s attempts in the activity, including the times it took for them to complete the mirrored/non-mirrored. In the .sav file in this week’s modules, forty-two actual pieces of data were selected at random (assuming that they had completed the square), and their performance times were put there. Below is an example of what you can see in the gallery, from someone who clearly got frustrated during the second attempt (as a note, your mirrored attempts should NOT look like this, give it your best shot).
SPSS Lab Rationale
In PSY 205, you should have learned about the one-way ANOVA, a statistical analysis that serves as an alternative to the independent-samples t-test, being able to compare three or more groups without inflating the likelihood of making a Type I error (if any of you would like a tutorial on how to conduct an one-way ANOVA in SPSS, click
here Links to an external site.
). The repeated-measures ANOVA, on the other hand, is an alternative to the paired samples t-test, where we look at the group across three or more different situations (in the case of this lab, we are looking to see if differences between non-mirrored and mirrored completion times improved across multiple trials). This will allow you to familiarize yourself with the concept of the repeated-measures ANOVA, as some of you may end up using it for your research projects.
Another goal of this lab is to introduce you to inputting data, something you may have to manually do after you collect your data for the study, depending on your technical capabilities. However, the most important outcome of this lab is the ending, where you will have to write the results section of this SPSS lab, just like a real research article you’d find in a peer-reviewed journal. At the end of the lab instructions, there will be an example of how you can report the results of a repeated-measures ANOVA, where you can use it as a guide when you are writing your results section.
Data Preparation
Open up the “MirrorTracingData.sav” data file with SPSS, click on “Variable View” to see the variables that you will have to input data for.
Now, you can return to “Data View,” where you will need to add the set of trials that you have completed, putting the following data into the values:
For “ID,” input the number 43 in the next row, as it would be the next trial.
For “Attempt 1 Time,” list how many seconds it took for you to trace the shape in the first attempt of the first trial. If you take over 60 seconds, convert the minutes into seconds. Repeat this for the five other attempts.
Lastly, we want to see the differences in time between the first, second, and third trials (i.e., differences between the first and second attempts, between the third and fourth, and between the fifth and sixth) to see if there was less of a difference between trials.
First, we’ll make the difference between the times in the first trial, which consisted of the first two attempts. Click “Transform,” then “Compute Variable.” B. Type “TRIAL1_DIFFERENCE” in the trial variable box.
Click on the parentheses key below the numeric expression box, then move in “Attempt 2 Time” into the numeric expression box with the window.
Press the minus key, then move “Attempt 1 Time” into the numeric expression box. The box should say “(ATTEMPT2_TIME – ATTEMPT1_TIME).”
Click “OK,” the variable should be created.
Do this two more times, now subtracting the third attempt from the fourth attempt, and the fifth attempt from the sixth attempt. They should be named “TRIAL2_DIFFERENCE” and “TRIAL3_DIFFERENCE” respectively.
Data Analyses
Now, we want to conduct a repeated-measures ANOVA to compare the differences between the trials (i.e., differences between the first and second attempt, third and fourth attempt, and fifth and sixth attempt) to see if people had a decreased difference between the non-mirrored attempts:
Click “Analyze,” “General Linear Model,” and “Repeated Measures.”
Name the within-subject factor “TIME_DIFFERENCE,” there are three levels.
Click “Define.”
Move the difference variables over to the within-subjects variables box. Make sure they are ordered 1, 2, 3, from top to bottom. This is very important!
Click the “Plots” box to the right, move “TIME_DIFFERENCE” into the horizontal axis box. Click “Add.”
Make sure that “Line Chart,” “Include Error bars,” and “Confidence Interval
(95.0%)” are checked. Click “Continue.”
Click the “Options” box to the right. In the new window, click “Desсrіptive statistics” and “Estimates of effect size.” Click “Continue,” then “OK.”
Conclusion
Write an APA-style results section to describe your findings from this lab.
State the null hypothesis you tested.
What did you conclude (i.e., did the amount of time it took to complete between the mirrored and non-mirrored attempts change with practice)?
What was the effect size (i.e., partial eta squared/η2? )? Would you identify this
effect size as strong, moderate, or weak?
Save your SPSS output file. Submit it, along with the results section, onto Canvas.
Example Results
The null hypothesis of there being no learning effect was tested. The alternative hypothesis predicted that differences in the participants’ times would differ between the three trials. Differences between mirrored and non-mirrored tracing times in trials 1, 2, and 3 were conducted using a repeated measures analysis of variance (ANOVA). The ANOVA found that there was a significant main effect between the mirrored and non-mirrored time differences, F(1, 41) ＝ 24.729, p ˂ .001, η2? ＝ .376, indicating a strong effect.
Tutorials for Reporting a Repeated-Measures ANOVA in APA Style
Written Links to an external site. Tutorial Links to an external site.
Video Links to an external site.
Tutorial Links to an external site.
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