Sheetnotes of the lectures or Introduction to Research Methods and Statistics 2018/2019 in English


Access options

The full content is only visible for JoHo WorldSupporter members with full online access.

  • For information about international JoHo WorldSupporter memberships, read more here.
  • Are you already a member?
    • During the account creation you can select 'I am a JoHo WorldSupporter Member with full online access'.
    • Became a member after you've created the account, or you upgraded your membership, then you can change the settings of your account on your WorldSupporter user page
  • or fill out the contact form

 

For Dutch visitors

Toegang tot pagina of document:

Word JoHo donateur voor online toegang

Je bent al donateur, maar je hebt geen toegang?

  • Log in, of maak een account aan als je dat nog niet eerder hebt gedaan op worldsupporter.org.
  • Bij het aanmaken van je account kan je direct aangeven dat je JoHo WorldSupporter donateur bent (met danwel zonder 'full online access', of je past dit later aan op de user page van je account
  • Kom je er niet uit, neem dan even contact op! Of check de veel gestelde vragen

Kom je er niet helemaal uit of heb je problemen met inloggen?

  • Lees de antwoorden op de meest gestelde vragen.
  • Of laat je helpen door één van de JoHo medewerkers door het online contactformulier in te vullen

-----------------------------------------------


JoHo WorldSupporter donateur worden

JoHo membership zonder extra services (donateurschap) = €5 per kalenderjaar

  • Voor steun aan de JoHo WorldSupporter en Smokey projecten en een bijdrage aan alle activiteiten op het gebied van internationale samenwerking en talentontwikkeling
  • Voor gebruik van de basisfuncties van JoHo WorldSupporter.org
  • Voor het gebruik van de kortingen en voordelen bij partners
  • Voor gebruik van de voordelen bij verzekeringen en reisverzekeringen zonder assurantiebelasting

JoHo membership met extra services (abonnee services) = €10 per kalenderjaar

€10 per kalenderjaar: Online toegang Only

  • Voor volledige online toegang en gebruik van alle online boeksamenvattingen en studietools op WorldSupporter.org en JoHo.org
  • voor online toegang tot de tools en services voor werk in het buitenland, lange reizen, vrijwilligerswerk, stages en studie in het buitenland
  • voor online toegang tot de tools en services voor emigratie of lang verblijf in het buitenland
  • voor online toegang tot de tools en services voor competentieverbetering en kwaliteitenonderzoek
  • Voor extra steun aan JoHo, WorldSupporter en Smokey projecten

Steun JoHo en steun jezelf door JoHo WorldSupporter donateur te worden

Direct Donateur Worden

Join World Supporter
Join World Supporter
Log in or create your free account

Why create an account?

  • Your WorldSupporter account gives you access to all functionalities of the platform
  • Once you are logged in, you can:
    • Save pages to your favorites
    • Give feedback or share contributions
    • participate in discussions
    • share your own contributions through the 7 WorldSupporter tools
Follow the author: Emy
Promotions
vacatures

JoHo kan jouw hulp goed gebruiken! Check hier de diverse bijbanen die aansluiten bij je studie, je competenties verbeteren, je cv versterken en je een bijdrage laten leveren aan een mooiere wereld

verzekering studeren in het buitenland

Ga jij binnenkort studeren in het buitenland?
Regel je zorg- en reisverzekering via JoHo!

Access level of this page
  • Public
  • WorldSupporters only
  • JoHo members
  • Private
Statistics
[totalcount] 1
Comments, Compliments & Kudos

Add new contribution

CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Image CAPTCHA
Enter the characters shown in the image.
WorldSupporter Resources
Work Group Excersices Introduction to Research Methods and Statistics - Psychology Bachelor 1, University of Leiden 2018/19

Work Group Excersices Introduction to Research Methods and Statistics - Psychology Bachelor 1, University of Leiden 2018/19


Week 1

These are the workgroup excersises of lecture 1 on 05/09/18

Introductory exercises

  1. What is the empirical cycle? ( Describe each of the phases briefly)
  2. What is a dependent variable?
  3. What is an independent variable?
  4. What are the two definitions within a study?
  5. What are the formulas for SS(total), SS(within) and SS(between)
  6. What is the relationship between these fomulas?
  7. Describe briefly the meaning of s2y, N, y, yij, nand Σ ?
  8. What is variance?
  9. What is the meaning of variance accounted for (VAF) and what is the formula for it?

Exercise 1

You are conducting a study about the differences in grades between boys and girls. In this study, you have six participants, three girls (G), and three boys (B). The data is given in the table below.

StyleijScore(yij - y)(yij - y)2yj(yj - y)(yj - y)2(yij - yj)(yij - y)2y
G119        
G218        
G317        
B125        
B224        
B326        
            
  • Calculate SS(total) 
  • Calculate SS(between)
  • What are the two ways of calculating SS(within)
  • Find the total, systematic and error variance.

Answers

Introductory exercises

  1. The empirical cycle is the process every study goes through and consists of five phases. Observation: the start of an idea for a research question. Induction: forming a general theory for your study. Deduction: specifying the study and forming your specific research hypothesis. Testing: Performing your experiment and gathering results. Evalution: What do the results say about your theory?
  2. The dependant variable is that what is affected by the experiment.
  3. The independant variable is that what causes change in an experiment.
  4. Conceptional, meaning 'what is it?' and operational, ' how do I measure it?' 
  5. Sums of Squares Formula
  6. SS(total) = SS(within) + SS(between)
  7. s2y = variance, N = number of observations, y = the grand mean, yij = the score of person i in group j, nj   = number of observations in group j and Σ  = addition
  8. Variance is the measure of variability
  9. VAF = the amout of systemetic variance withing the total variance. The formula = systemetic variance/total variance

Excersise 1

 

StyleijScore(yij - y)(yij - y)2yj(yj - y)(yj - y)2(yij - yj)(yij - y)2y
G1192,56,2581.52,25116,5
G2181,52,2581,52,25006,5
G3170,50,2581,52,25-116,5
B125-1,52,255-1,52,25006,5
B224-2,56,255-1,52,25-116,5
B326-0,50,255-1,52,25116,5
   39017,5 013,504 
    1. 17,5
    2. 13,5
    3. SS(within) is 4
    4. total = 3,5, systematic = 2,7, error = 0,8

     

    Week 2

    These are the workgroup excersises of lecture 2 on 12/09/18

    Introductory excersises

    1. What is a variable?
    2. When is a variable mutually exclusive?
    3. When is a variable exhaustive?
    4. Which five measurement levels can be distinguished?
    5. What types of bias can occur in self-reports?
    6. What are probability samples and which four types can be distinguished?
    7. What are non-probability samples and which three types can be distinguished? 
    8. What is a sampling frame and why is it useful?

    Excersise 1

    For this, pick out a random questionaire from the internet and analyse it to test your knowledge. Keep into consideration:

    • Do all the variables fullfil the requirements of mutual exclusivity and exhaustiveness?
    • What is the level of measurement of each variable?
    • Are there any questions that might be suseptible to any self-report bias?
    • How can this be solved?
    • Can you see what kind of sampling is being used?
    • What is the sampling frame?

    Excersise 2

    There are two research applying for a study. Researcher A is interested in to what extend people in The Netherlands suffer from depression and how severe their symptoms are. Researcher B wants to see which treatments are being uses at the moment for people who have 'bipolar disorder'.

    Identify for each of the two researchers what population they are studying, what their sampling frame is, howthey might get their hands on it and which sampling method would be most appropriate.

     

    Answers

    Introductory exercises

    1. A variable is the measurement that varies in value of a level.
    2. When there is no overlap between scores. 
    3. When no oneor nothing is excluded from the values.
    4. Nominal, ordinal, interval, ratio, absolute.
    5. Social desirability, acquiescence and nay-saying response style
    6. Each individual has the exact same, fixed probability. The four types are: simple random, systematic, stratified random and multistage cluster
    7. The probabilities between people are not fixed and can vary. Three types are: Convienience, quata and purposive.
    8. It's a list of all individuals in a population and it can help you pick your sampling group.

    Excersise 2

    Researcher A: The population is everyone in The Netherlands. The sampling frame is everyone living in The Netherlands and they might obtain is through a governmental institution. The sample method would be multistage cluster sampling.

    Researcher B: The population is everyone with a bipolar disorder in The Netherlands. This is also the sampling frame and might be obtained through therapists or hospitals. The sample method would be stratified random sampling.

     

    Week 3

    For the exercises and information from week 3 and 4, You need to be in possesion of the IBM SPSS Statistics 25 program on a computer or laptop.

    How to work the SPSS basics

    1. When starting SPSS, it always opens two windows, your Data Editor and yoor Output Window. Never close either of them without saving, but especially not the Output Window, as it shows all the changes you have made to your Data Editor file.
    2. The Codebook is your best friend. It's a table that shows you exactly what your variables mean and what their values are. Before starting any SPSS work, make sure you first look at the codebook.
    3. When editing your variables, go to variable view (bottom left) and identify your variable under 'name'. Under 'type', you can decide whether your variable is numeric, such as a score of a test, or string, meaning there is a worded meaning behind it, such as gender.
    4. Important is that SPSS works with numbers, and you have to tell it what those numbers mean. Under 'values', you can define what each number means. (E.g. 1=female, 2=male, 9=unknown)
    5. A missing value is when a responded has been unclear on a question of didn't answer it. They are usually defined with a special number and your codebook will tell you what that number is. If you want SPSS not to count those numbers in with calculations, you go to 'missing', click 'discrete missing' and define the number(s) as a missing value.

    Practise

    Start up SPSS and put the following Data in the program

    IDV1V2V3V4
    11701.781
    22559.994
    39731.752
    429991.703

    Define the variable labels, the value lables and the missing values, using the codebook.

    NameTypeLabelValues/Missing
    IDNumRespondent number 
    V1NumSex1=female, 2=male, 9=unknown
    V2NemWeight in kilograms999=unknown
    V3NumHeight in meters9.99=unknown
    V4Num'I love Brussels'

    1=strongly agree, 2=agree, 3=undecided, 4=disagree, 5=strongly disagree, 9=unknown

     

    Sorting, selecting and splitting

    1. To Sort data, go to 'data' (4th label up top). Press on 'Sort Cases' and drag the variable you want sorted into the box. Press either ascending or descending and click OK
    2. To Split data, go to 'data', 'split file' and click on 'compare groups'. 
    3. To Select data means that you want SPSS to only take certain data into consideration. Go to 'data', 'select cases' and click the 'If condition is satisfied'. This allows you to tell SPSS when and when not to count in data. 
    4. To create charts, go to 'graphs' (7th label up top). There, press the chart builder and drag from the gallery the type or chart that you want. Identify the variables on the x and y axis and press ok. THe chart will now show in your output window. 

    Practice

    Try out selecting, splitting and sorting in the file you just made. Then, make a bar chart. Save the file as test.sav afterwards

     

    Week 4

    For this tutorial, you will need the IBM SPSS Statistics 25 program.

    Case summaries, frequency tables and descriptive statistics

    1. To make a case summary, go to 'analyse' (6th label up top) and go to 'report'. There, you will see 'case summary' and you can decide of which variables you want to see a summary of. After pressing 'ok', the summary will appear in your Output Window.
    2. To make a frequency table, go to 'analyse' and then 'descriptive statistics'. There, you will find 'frequencies'. Select the variable you want to know the frequency of and press ok. If you want to find a certain frequency distribution, go to 'options' and select your distribution before pressing ok.
    3. To get descriptives such as the mean or median, go to 'analyse' and then 'descriptive statistics', where you can see 'descriptives'. Choose your variable and press 'options'. Here you can decide exactly which descriptives you want. Then press ok.

    Practise

    Open the test.sav file and create at least 4 more fictional variables of different types of values, one of which being age, and 4 more respondents. Then, find the mean of the weight of all eight respondents and show the Q1 and Q3 of the frequencies.

    Boxplots, computing and recoding

    1. With a boxplot, you can also show the frequency distributions or descriptives. Go to 'Graphs' and make a boxplot. Keep in mind that you can select either a single boxplot or multiple ones. With the latter, you can also show that difference between groups. To change a visual thing about the boxplot, such as the colour, press on the graph and an editor window will pop up.
    2. When you want to compute a variable, go to 'transform' (5th op top) and select 'compute variable'. Here, you can decide which variable you want to make into something else, or what you want to know. 
    3. Redoding means that you are changing the values of a variable into something new. Go to 'transform' and then 'recode into differnet variables'. Select which variable you want to recode, what the new name will be and then press 'Old and new values...' Here you an tell SPSS exactly what old variable turns into what new one.  

    Practise

    Make a purple box plot of you test.sav file. Then, compute a variable for the age in months and put the 'I love Brussels' variable into catergories, (strongly) disagree now being 1, undecided being 2 and (strongly) agree being 3.

     

    Week 5

    Introductory exercises

    1. What is a normal distribution?
    2. What is the meaning of µ, σ, P, ¯x, sx, <, and ≥?
    3. What is the effect of standardizing on the parameters of a distribution?
    4. Why is it useful to standardize a variable and what is the effect of standardizing on the shape of a distribution?
    5. What is a z score and how do you calculate it?
    6. How could you calculate the X of a z-score?
    7. What is the 68-95-99.7% rule?

    Practise

    An psychologist has developed an instrument to measure CEO qualities in people. The scores of 800 managers have approximately a normal distribution with µ = 34.00 and σ = 7. Five of these scores are in the table below.

    Respondend nr.  X  zx  P(Z<z)  P(Z ≥ z)
    130   
    238   
    346   
    460   

     

    Answers

    1. A normally distribution has a big amount of average scores, with very few high or low scores. It is always symmetrical and normally skewed.
    2. µ = the mean, σ = the standard deviation, P = probability, ¯x = the mean of x, sx = standard deviation of x, < = smaller than, and ≥ = bigger than or equal to.
    3. µ = always 0 and σ = always 1
    4. To make sense of the data you have been given without any context. The shape of the distribution does not change with standardizing. 
    5. Z- score is a way of standardizing and the formula is {\displaystyle Z={\frac {X-\mu }{\sigma }}}
    6. Reformulate the formula to X =  µ + z * σ
    7. Between -1 and +1 standard deviation is 68% of the curve. Between -2 and +2 is 95% and -3/+3 is 99.7%. This is often referred to as the 68-95-99.7% rule.

    Practise answers

    Respondend nr.    X      zx  P(Z<z)  P(Z ≥ z)
    1  30 -.57 .2843 .7157
    2  38  .57 .7157 .2843
    346 1.71 .9564 .0436
    460 3.71>.9998 <.0002

     

    Week 6

    Introductory questions

    1. Which graph can show association between two variables?
    2. How can you describe the association between variables?
    3. What influence can outliers have on the association between  variables?
    4. What is the meaning of the following symbols: ¯x, ¯y, sx, sy, sxy and rxy?
    5. How do you calculate the covariance?
    6. What are the two formulas for calculating Pearson r and which values can it have? What is the rule of thumb for Pearson r?
    7. What is the formula for calculating z scores?

    Practise

    A  psychologist studied the ways in which children learn to calculate. In a random sample of 9 children in the ages between 7.5 and 8.0 years old he studied a child’s mental age, X, and his or her math ability, Y. The data can be found in the table below.

    RespXySexClass
    16.516.5M1
    28.521.0F2
    37.022.5F3
    45.518.0M1
    510.024.0F3
    68.022.5M2
    76.519.5M1
    88.021.0M3
    97.524.0F

    3

    1. Draw the scatterplot of the relationship between X and Y.
    2. Formulate a  conclusion about the association between mental age and math ability.
    3. Aaccommodate a third variable in the scatterplot.
    4. Describe the relationship between X and Y for the boys and girls separately while in the same scatterplot.

    Answers intro questions

    1. A scatterplot
    2. Direction, strength and shape
    3. Outliers can heavily influence correlation is they are located far from the others.
    4. ¯x = mean of x, ¯y = mean of y, sx = standard deviation of x, sy = standard deviation of y, sxy = standard deviation of x and y / covariance of x and y andn rxy = pearson's r of x and y
    5. Sxy = ∑ (xi - x)(yi - y)/ (N - 1)
    6. rxy = ∑ zxz/ n - 1        or         rxy = sx/ sxs
    7. Z = X - µ / σ

     

    Week 7

    For this tutorial,

    Read more