Basics of SPSS Part 1 (2014-15)

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Getting started entering data and defining variables Part 1

BEEC

Dr. Christine Pereira Academic Skills Team (ASK) ask@brunel.ac.uk

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» Purpose and use of SPSS » Open SPSS

» What is a Variable? » Defining variables in SPSS

» Entering Data

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» Open and save data files » Import data from Excel

» Get SPSS on your own computer » Have a go using some sample data (or your own) ASK at Brunel (2014-15)

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» SPSS is a Statistical Software Package » SPSS is a tool  It only does what it’s ‘told’ to do.  It does not think for you  It is not a black box

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» You need to know the correct statistics for your research BEFORE using SPSS. » If you understand the statistics, then you are ready to do analysis in SPSS.

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Select SPSS 20 from the list

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Type SPSS 20 into the search box

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Click on the Windows Start Icon

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Open NEW data file

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Enter variable names in the first column of Variable View.

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We will look at all the columns in more detail shortly.

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Each variable name will appear as a column heading replacing var.

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Enter the data for each variable.

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What is a variable? How do we define variables in SPSS?

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» A measurement:  A characteristic + E.g., Gender, Age, Height, Weight…

 Time points + E.g., pre-test, post-test, T0, T1, T2…

 Experimental Condition + E.g., Condition, Experimental group…

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 Opinion/belief + E.g., A survey question which asks for a respondent’s level of agreement with a statement

 Etc… ASK at Brunel (2014-15)

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What is your gender?

Male or Female ASK at Brunel (2014-15)

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How long does it take, on average, to commute into Uni? ASK at Brunel (2014-15)

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What is your main mode of transport to Uni? ASK at Brunel (2014-15)

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Indicate your level of agreement with this statement: “Most days, my commute causes me to feel stressed when I arrive at university�. ASK at Brunel (2014-15)

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Country name is unique – participant ID not needed

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Number of births per 1000 people

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Surplus/deficit as % of GDP

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Gov debt as % of GDP

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Questionnaire Responses Age (in years)

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3pt Likert Scale Agree No opinion Disagree

200 residents Uxbridge

Agreement with stem cell research

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5pt Likert Scale Strongly agree Agree Neutral Disagree Strongly disagree

Is global warming important?

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Questionnaire Responses Age

StemCell

GlobalWarming

1

23

Agree

Strongly Agree

2

28

Undecided

Agree

3

47

Undecided

Strongly Disagree

4

62

Disagree

Undecided

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Resident

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Experimental Condition

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Cond 1 and 2 are independent, NOT repeated measures.

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Score on a test

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Low Lower middle Middle Upper middle High (OECD*) High (non-OECD)

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*OECD (Organisation for Economic Co-operation and Development)

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East Asia & Pacific Europe & Central Asia Latin America & Caribbean Middle East & North Africa North America South Asia Sub-Saharan Africa ASK at Brunel (2014-15)

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Caffeine and Sleep

Condition 30

Average hours slept Over 2 weeks

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participants

Measure

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Caffeine and Sleep Condition

AvgHoursSlept

1

Control

7.2

2

Caffeine

6.7

3

Caffeine

6.3

4

Control

6.9

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Participant

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Status when admitted to care facility ASK at Brunel (2014-15)

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Anxiety level measured at 3 time points for each participant ASK at Brunel (2014-15)

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Why not enter TIME as 1 variable like we did for STATUS?

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Birth rate per 1000 measured at 3 time points for each country

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Fitness Regime

PROFESSIONAL train

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50 Participants SELF train ASK at Brunel (2014-15)

One mile time trial

BEFORE

AFTER

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Fitness Regime Participant

Training

Before_Mile (min)

1

Self

15.3

14.1

2

Professional

16.1

14.9

3

Self

20.5

16.8

4

Self

16.8

16.2

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After_Mile (min)

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Variables

Categorical

Scale

Qualitative

Quantitative

Nominal

Ordinal

(Unranked categories)

(Ranked categories)

 

Marital Status Political Party Eye Color

Satisfaction level Level of agreement

Not grouped    

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Height Weight Age No. of cars No. of students

• In SPSS, data is either Nominal, Ordinal or Scale. • It is essential to classify data correctly. - Incorrect classification… may result in incorrect analyses. ASK at Brunel (2014-15)

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Code categorical variables Enter data

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Level of Measurement?

Categorical variables need to be coded Scale variables do not need to be coded ASK at Brunel (2014-15)

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0 0 1 0 1 1 0 1 0 1

Level of Measurement?

0 = Male 1 = Female ASK at Brunel (2014-15)

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Level of Measurement?

Scale, does not need to be coded ASK at Brunel (2014-15)

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Level of Measurement?

1 1 2 1 1 1 3 4 1 2

1 = tfl (i.e. public transport) 2 = Car 3 = Cycle 4 = Walk ASK at Brunel (2014-15)

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Indicate your level of agreement with the following statement:

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“Most days, my commute causes me to feel stressed when I arrive at university�.

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Level of Measurement?

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1 = Strongly Disagree 2 = Disagree 3 = I don’t know 4 = Agree 5 = Strongly Agree

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Data has been coded Now we’re ready to enter it in SPSS ASK at Brunel (2014-15)

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1. Enter & define variables from Variable View.

• Variable names • Must begin with a letter • No spaces and no special characters (except _ ) ASK at Brunel (2014-15)

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Dr. Christine Pereira

1. Enter & define variables from Variable View.

• Type • Should (almost) always be numeric • SPSS cannot analyse non-numeric data ASK at Brunel (2014-15)

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Dr. Christine Pereira

1. Enter & define variables from Variable View.

• Decimals • How many decimal places do you want to see in the Data View? ASK at Brunel (2014-15)

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Dr. Christine Pereira

1. Enter & define variables from Variable View.

• Label • IMPORTANT!!! Make good labels! • Short description of the variable • This is what will be written on all graphs & tables ASK at Brunel (2014-15)

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Dr. Christine Pereira

1. Enter & define variables from Variable View.

• Values (i.e., Value labels) • IMPORTANT!!! - Tell SPSS what all the codes represent! • This is what is written on all graphs & tables ASK at Brunel (2014-15)

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Dr. Christine Pereira

1. Enter & define variables from Variable View.

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Dr. Christine Pereira

1. Enter & define variables from Variable View.

• Missing • Missing data can be coded too • Chose a number not in the data, like 99 or 999 • Replace all missing values in your data with this code first ASK at Brunel (2014-15)

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Dr. Christine Pereira

1. Enter & define variables from Variable View.

• Measure • Level of Measurement (Nominal, Ordinal, Scale) • By default ALL new variables are unknown • YOU must choose the appropriate measure ASK at Brunel (2014-15)

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2. Enter data from Data View.

• Variable names • Will become column headings in Data View. ASK at Brunel (2014-15)

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Now, let’s enter some data ASK at Brunel (2014-15)

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Saving and Opening Data or Output Files

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Locate a folder to save it in:

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 On your H drive OR  On your pen drive

 Name it appropriately  Extension .sav ASK at Brunel (2014-15)

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 Shows output for ALL analysis run in SPSS  Keeps a log of all activity of open data files  Saved with the extension .spv

Everything done in SPSS is shown here, in outline form. ASK at Brunel (2014-15)

A data file was saved as SPSS Workshop Example.sav and logged in the output file.

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New data file

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New output file

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Existing data file

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Existing output file

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Importing data from Excel

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Click here

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Save this file to your H: drive or pen drive

Click here ASK at Brunel (2014-15)

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» Can be .xls OR .xlsx

» Variable names CAN be imported too  Must be in row 1 of the worksheet  They will be imported to the Variable View

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» Data will appear in SPSS Data View

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Filename (.xlsx)

Variable names

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(Row 1)

This sheet contains the coded data ASK at Brunel (2014-15)

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Existing data file

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Select the Excel file

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Find the folder where you saved the file

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Choose Excel file type to see your .xlsx 63


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Choose the correct worksheet

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Variable Names

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(from Row 1)

View all data ASK at Brunel (2014-15)

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This variable name from Excel could not be used. SPSS made it a label and created a new variable name ASK at Brunel (2014-15)

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Remember to change the level of measurement

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Watch it here https://www.screenr.com/BknN

Read it here

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http://issuu.com/christinepereiraaskbrunel/doc s/download_spss_onto_your_own_compute/1

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Short video tutorials on all these topics

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Dr. Christine Pereira

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» Variables go in columns

» Categorical data should be coded first » If you import data from Excel, make sure to:  Put variable names in the first row  Code your categorical data first, then import codes

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» If you choose to code missing data:  First, replace all missing values with the code  Second, define the missing value code in the Variable View

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» SPSS Survival Manual, 4th Edition (2010) by Julie Pallant. » SPSS Survival Manual, 5th Edition (2013) by Julie Pallant.

Dr. Christine Pereira

» Discovering Statistics Using SPSS, 3rd Edition (2009) by Andy Field. » Discovering Statistics Using SPSS, 4th Edition (2013) by Andy Field.

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» Caffeinated drinks: http://www.google.co.uk/url?sa=i&source=images&cd=&cad=rja&uact=8&docid=Y9I7e2I59JjPCM&tbnid=sr6aMiG082v7UM&ved=0CAgQjRw &url=http%3A%2F%2Fslapenergydrink.com%2Fenergy-drinkscaffeine&ei=N30lVIqPFKid7ga_44EQ&psig=AFQjCNEPc4cpRWQBaBOKS9zoUsC_0DaV9w&ust=1411829431470911

» People in experiment: http://www.google.co.uk/imgres?imgurl=http%3A%2F%2Fezquants.weebly.com%2Fuploads%2F1%2F3%2F4%2F4%2F13445934%2F47970_o rig.gif&imgrefurl=http%3A%2F%2Fezquants.weebly.com%2Ft-test--the-nullhypothesis.html&h=270&w=315&tbnid=pCG2pi0OBEM6yM%3A&zoom=1&docid=9W6CFf18UFyRM&ei=YoIlVKKBBLSS7AbotoGABg&tbm=isch&ved=0CHEQMyhKMEo&iact=rc&uact=3&dur=350&page=4&start=73&ndsp=23

» Placebo: http://www.google.co.uk/imgres?imgurl=http%3A%2F%2Fimage.yaymicro.com%2Frz_1210x1210%2F0%2F5e9%2Fplacebo--pill-with-no-medicinal-effects-in-control-group-of-stu-5e98de.jpg&imgrefurl=http%3A%2F%2Fyaymicro.com%2Fstock-image%2Fplacebo--pill-with-no-medicinal-effects-in-control-group-ofstu%2F1662248&h=1028&w=1210&tbnid=EUdctbyqvrlO4M%3A&zoom=1&docid=aAnQenPGWluQ7M&ei=YoIlVKKBBLSS7AbotoGABg&tbm=i sch&ved=0CGgQMyhBMEE&iact=rc&uact=3&dur=272&page=3&start=46&ndsp=27

Dr. Christine Pereira

» Caffeine tablets: http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=0NqTET17JodZNM&tbnid=eB_SUbuyiKHgM:&ved=0CAcQjRw&url=http%3A%2F%2Fwww.drugstore.com%2Fnatrol-caffeine-100-mg-fast-dissolve-tabletsmocha%2Fqxp450974&ei=pIMlVIqzHIfjOnZgDA&bvm=bv.76247554,d.ZGU&psig=AFQjCNGvhc0bHr1wLewiqAgLuep9lV5BGA&ust=1411831016411090

» Sleeping: http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=9c3klNdFBhfBCM&tbnid=KUe-mlLOZJGBM:&ved=0CAcQjRw&url=http%3A%2F%2Fwww.rewordit.org%2Fwhy-your-body-love-tosleep%2F&ei=boUlVNKnIIy_PPfPgcAB&bvm=bv.76247554,d.ZGU&psig=AFQjCNG7qafjwsNMdRYchIgLrBb42tSeiA&ust=1411831519554208

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» Silhouette runners, silhouette collection: running, vol:42. http://freedesignfile.com/upload/2012/10/running_people_03.jpg

» Clip art for professional train participants: http://www.google.co.uk/imgres?imgurl=http%3A%2F%2Fwww.livingwellcic.com%2Fwp-content%2Fuploads%2F2013%2F07%2FHIV-andStigma-Study.jpg&imgrefurl=http%3A%2F%2Fwww.livingwellcic.com%2Fnews%2Fhiv-services%2Fhiv-andstigma%2F&h=400&w=472&tbnid=noisZZOR1Xx1AM%3A&zoom=1&docid=CYtMWBe02aU7M&ei=hUMpVJWrJsP0apLMgUA&tbm=isch&ved=0CC8QMygHMAc&iact=rc&uact=3&dur=267&page=1&start=0&ndsp=14

» Clip art for self-train participants:

Dr. Christine Pereira

http://www.google.co.uk/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&uact=8&docid=IbKSqXDNyckLHM&tbnid=CGxPa Nadhe4VdM:&ved=0CAcQjRw&url=http%3A%2F%2Fwww.nearingkolob.com%2Fmormonism-dead-zombie-rituals%2F&ei=0MpVNW6IsGVaqqsgKAG&bvm=bv.76247554,d.d2s&psig=AFQjCNH1emvHrdw_DEn15T4LJV7cjxhrfw&ust=1412076805987563

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Dr. Christine Pereira

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