Psychology

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Wee6Day1.pptx

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Week 6, Day 1

PSY 3215 U01B 1215, Lab

Lab Overview

Part I: Advanced Analyses in SPSS

Part II: Odds & Ends for your Final Paper

Part I Advanced Analysis in SPSS

Part I Setting up

In this section, we’re going to be covering how you can do advanced analyses in SPSS; looking at two or more independent variables would fall under this example

To begin, let’s go back to the in-class practice data that was used for the second half of last week’s day 2 lecture

Canvas  Modules  Example Data  In-Class Practice Data

Part I Pruning data

It’s very common to eliminate a portion of your data in a study to focus on a smaller subset. For example, let’s say you wanted to eliminate all the ratings of Strawberry ice cream from your data so you can just focus on comparing Chocolate vs Vanilla…

To start this, in SPSS go to…

Data  Select Cases

Part I Selecting specific data

Now, what you want to do is select only the data you want to work with.

In this case, that’s the chocolate and the vanilla data

Go to the Select Box, then hit the

If button from “If condition is satisfied”

Part I Selecting specific data

Now, be sure to enter exactly:

(flavor = 1)|(flavor = 2)

Then hit Continue at the bottom of the box

What you have just said is:

Only select data if the flavor variable is 1 or 2 (in our case, vanilla or chocolate)

Part I Selecting Specific Data

Now that you have the right select condition, make sure the output is set to “Filter out unselected cases” and then hit Ok

Your data will no long analyze any strawberry ice cream measures

Part I Basic uses of selected data

Now with your data selected specially, you can do things like look at the mean rating for ice cream, but without strawberry

Remember, to find the mean variable, go to Analyze  Descriptive Statistics  Descriptives

From there, you would select the rating and look at the descrptives

Part I More advanced analyses

However, now that we’ve pruned out the strawberry data, we now have a chance to look at ratings based on a 2 x 2 design

In addition to flavor, there is another independent variable in the data: store

In this data, ice cream was sold at one of two stores

1: Uptown

2: Downtown

It can be useful to see if there’s a different in the rating based on flavor, but what if we also wanted to see if there was a different in rating based on store (looking at 2 IVs, each with 2 levels/groups)

Part I More advanced analyses

To start this, go to:

Analyze  General Linear Model  Univariate

This will let us look at a single variable (single – uni; variable – variate; univariate!) in the context of multiple independent variables

Part I Univariate Analysis

To set this up properly, first:

Move the dependent variable (rating) to the Dependent Variable box

Next, put your two IVs (flavor & store) in the Fixed Factor(s) box

Independent variables are sometimes called fixed factors because they are a fixed/unchanging part of your study; something that is predetermined

Part I Univariate analysis – The details

Now, you’re going to want to check to see if our DV (rating) is affected by either of our 2 IVs

However, when looking at 2 or more IVs with two or more groups, something interesting can happen

You can get what’s called an interaction effect; something where both the IV 1 & IV 2 together are having a special influence on the DV measure

For our example, this might mean the rating for uptown chocolate ice cream is better than either the effect from uptown or the effect from chocolate ice cream!

Part I Univariate analysis – The details

To look for this kind of effect, go to the EM Means box option on the side

While here, make sure you have all three options moved to the “Display Means for” box, and select the “Compare Main Effects” box

Part I Univariate analysis – The details

Hit Continue  Ok, then go to look at the output window

From here, we can see that both the flavor & the store variables had a significant influence on how much people rated enjoying their ice cream!

Do you think there was any kind of special interaction between the flavors & the store?

Part II Misc Notes

Part II - Misc notes Final paper Content

Abstract

Remember: Purpose of Research, Study Design, Sample Size & Unique Characteristics, Statistical Analyses

Our statistical analyses is the paired-samples t-test that was covered in last week’s lab

Appendix

Demographics & Consent

Start each one on it’s own page and make sure to label it!

Part II - Misc notes Final paper Content

Overall Writing Quality

Make sure to check your tense – the rubric for Experimental Paper I can help with this

Make sure to use scientific and objective terms; no slang, vernacular or abbreviated words (even if the abbreviated word can pass as a regular word!)