Seminar 2 (2011)

Data entry, analysis using SPSS and WoK

Why do we need stats?

Coin toss

Birthdays

Lady gaga

2

Can you toss a coin and get 10 heads in a row? (without cheating)

Derren Brown: The Events: The System

http://www.youtube.com/watch?v=WMqrFhhhw18

What if somebody offered to bet that at least two people in your in this class had the same birthday?

Would you take the bet?

4

Lady Gaga

6

Paparazzi Reversed

http://www.youtube.com/watch?v=TyZNj93CmhQ

Bad Romance (Misheard lyrics) - Lady Gaga

http://www.youtube.com/watch?v=4Bg9M_GjqVg

Why do we need stats?

Coin toss…. Given a lager enough data set you can find the pattern you looking for.

Birthdays …. We are bad a estimating probabilities.

Lady gaga…. When we are primed we can see patterns.

7

Structure for this session

Explain memory experiment from last week

Input this data into SPSS

Create the variable of interests using the COMPUTE function.

Create statistics.

Graph data

Introduction on how to use Web of Knowledge for your literature search.

Group RememberingLast week you were ask to take part in an experiment in which you will view a series of 24 items list.

You then were asked to recall words – Individually – In a group

Participants with even module reference numbers were told they were in groups of 2.

Participants with odd module reference numbers were told they were in groups of 5.

However in the group recall condition participants were not in a groups all saw the same words recall.

What we are testing is whether recall improves when people believe are working in a group.

We also wanted to see if perceived group size has an effect on recall.

Some questions about the group

remembering experiment

What are our independent variables here?

What have we measured (i.e. what specifically is the dependent variable)?

What possible issues are there with the experiment design?

Participants

From the SPSS file we will find out

The number participants in total and in each group.

The number of males and females

The average and range of the participants age.

Materials Target items were 4 lists of 24 unrelated words.

List of words matched so they were all:– Letters: 3-8– Syllables: 1-3 – Familiarity ratings:550-700

Items were presented and recalled using a bespoke computer program.

Items and trials were presented in a random order.

Design

There were two IVs:

1. Within-subjects: Individual vs. group recall

2. Between-subjects: Perceived group size (2 or 5)

The DV was number of words recalled.

Order of conditions was counterbalanced across participants.

The number of words “recalled” by the false group members was matched across group size

Procedure Participants were shown a list of 24 words. The list was presented for 1 minute.

Participants had a 1 minute delay.

In the individual recall condition, participants were then given 1 minute to recall as many words as possible on their own using an internet-based chat program.

In the group condition, participants were told that they had been randomly assigned to groups of either 2 or 5 people who had to collaboratively recall as many words as possible in 1 minute using an internet-based chat program.

In reality, each participant was recalling words alone, while a computer program simulated the other group members’ contributions of 8 items.

You need to create variables for: Participant ID: (Remember to select appropriate data ‘Type’)Gender : Values 0 = ‘Female’ and 1= ‘Male’.Age:Group size: Values 0 = ‘two people’ and 1 = ‘five people’.Individual score 1:Individual score 2:Group score 1:Group score 2:

Go to “Variable view and enter in the variables you need.

Complete questions 1 to 5

on the worksheet

Mean score

Use the COMPUTE function to create a new verbal called Mean Individual score.

The new variable should be the average of Individual score 1 & Individual score 2

Now repeat the process to create a new verbal called Mean Group score

How to perform t-tests in SPSS

Within-subjects t-test

Between-subjects t-test

T-tests are listed under ‘Compare Means’

How to do an independent-samples t-test using SPSS

An independent-samples t-test involves comparing two different groups on a single dependent variable.

Between-subjects t-test

Dependent variable (DV) goes hereIndependent variable (IV) goes here

For the IV SPSS needs to be told what the label numbers are of the two groups we want to compare

22

Means and Std. Deviations of the two groups on the DV

Are two rows for the t-test result. Only one row, defined by the result of the Levene’s test, is looked at

If the significance for Levene's test is:

greater-than (>) .05 use the top row “Equal variables assumed”.

.05 or below (=<), then use the bottom row "Equal Variances not

Assumed" .

If the significance for Levene's test is 0.05 or below, then use the bottom row "Equal Variances not Assumed" test. Otherwise use the top row “Equal variables assumed”.

Levene's test is greater than .05 therefore we need to use the top row.

t=2.49 df=98 p=.015

There was a significant effect of perceived group size, t(98)=2.49 p=.015. Participants recall a grater number of items when they thought they were in a group of two (M=5.66, SD= 1.44) as apposed to a group of 5 people (M=4.92, SD=1.53)

If the significance for Levene's test is 0.05 or below, then use the bottom row "Equal Variances not Assumed" test. Otherwise use the top row “Equal variables assumed”.

Levene's test is less than .05 therefore we need to use the bottom row.

t=2.49 df=97.56 p=.015

There was a significant effect of perceived group size, t(97.56)=2.49 p=.015. Participants recall a grater number of items when they thought they were in a group of two (M=5.66, SD= 1.44) as apposed to a group of 5 people (M=4.92, SD=1.53)

How to do a paired-samples t-test using SPSS

A paired samples t-test would allow us to compare the same participants performance on 2 variables

Within-subjects t-test

Mean for individual scores Mean for group scores

Means (and SDs) for the two variables

Mean difference between the two variables

Standard deviation of the difference between the two variables

t = 19.71Note: we ignore minus signs when reporting t values

df=49 p <.001

p=.0000000000000000000000000000000000004738209580081584

28

There was a significant effect of perceived group, t(99)=19.71 p<.001. Participants recall a grater number of items when they thought they were working on there own (M=8.93, SD= 1.18) as apposed to a group (M=5.29, SD=1.53)

t=19.71 df=99 p<.001

We are going to stop for 20 min so you can

work through questions 6-9 on the worksheet and have

a break

Producing a Clustered bar chart

30

Choose summaries of separate variables

Chose Clustered chart

Put the variables that you want to plot here

Click to include error bars

Put the variable that you want used to cluster the bars here

Edit your Graph

Structure for this session Explain memory experiment from last week Input this data into SPSS Create the variable of interests using the COMPUTE function. Create statistics Graph data

Introduction on how to use Web of Knowledge for your literature search.

Web of Knowledge

A bit like Amazon for journal articles

http://www.isiknowledge.com/

The main simple search page for Web of Knowledge (WoK)

You can use the tabs as the top to select

different Databases, e.g. Web of Science

To Connect Web of Knowledge if you are off-campus you will need to use your ATHENS account.

More information can be found on the library website.

You have to tell WoK which part (or field) of the record to search in

I want to search for records on the topic of Dyslexia, how ever I don’t want to exclude records that have slightly different endings e.g. Dyslexic.

So you put a * to represent unknown characters. WoK knows it is not the end of the word and I want to include any group of characters that follow Dyslex

You can search in more than one field or add more than one search term

You can also use this to exclude records by selecting NOT

A good way to find a particular article in Web of Knowledge is:

Use 1 or 2 words from the Title

Use the name of 1 Author

Search for the Year Published

This tells me what search I did to get the result

This tells me how many results I have got

You can sort your results by different factors

here

You use these options to narrow down your results further by selecting options (like eBay or

Amazon), or searching with in your results.

The numbers in brackets are how many results you be left with if you select that option

Endnote is a really helpful

resource which you can go to aLibrary Training

session on

Clicking in this Icon will tell you if you can get a copy of the article in full from Brookes

LibraryThis tells you who has cited

the article

This is where you can ask WoK to search for related resultsThis is where you can see

articles that are cited by this article

For the rest of the class use Web of Knowledge to answer the rest of

the questions on the worksheet.

Enter your answers in to the online form.

On the psychology resources page for U24103 under Links Seminar 2 worksheet

For your practical report

You should reference the 3 journal articles on the resources page.

You also need to find and reference 2 relevant journal articles that have been published since 2002.