IB Psychology Internal Assessment Higher Level 20% of final grade Standard Level 25% of final grade

The Task Replicate an experiment that manipulates an Independent Variable Write a report conforming to IB guidelines

IA Differences between SL and HL Weighting: 25% Replicate a published experimental study; Characteristics of SL simple experimental study: Limited in scope Involves the manipulation of only one independent variable Involves the measurement of only one dependent variable Requires the use and interpretation of the descriptive statistics Does NOT require the use of inferential statistics ; State the aim of the study. Weighting: 20% HL students: may undertake a replication or a modification of a published experimental study; Are required to undertake more extensive background research related to their simple experimental study; 3 studies!!! State an operationalized experimental hypothesis; State an operationalized null hypothesis; Apply inferential statistical test to their data and interpret the result of the test.

Internal Assessment Criteria SL A – Introduction – 2 marks B – Method: Design – 2 marks C – Method: Participants – 2 marks D – Method: Procedure – 2 marks E – Results - 4 marks F – Discussion – 6 marks G – Presentation – 2 marks Total: 20 marks HL A – Introduction – 5 marks B – Method: Design – 2 marks C – Method: Participants – 2 marks D – Method: Procedure – 2 marks E – Results: Descriptive- 2 marks F – Results: Inferential – 3 marks G – Discussion – 8 marks H – Citation of sources – 2 marks I – Report format – 2 marks Total: 28 marks

Step 1: Choosing an experiment to replicate Guidelines: Ensure that the study has an IV that you can manipulate (not gender/age/culture) e.g. verbs, background noise. Your experiment should be relatively easy to replicate, cognitive experiments concerning memory are best suited to the Internal Assessment. You must clearly justify and operationalize your hypotheses.

Step 1: Choosing an experiment to replicate Guidelines: You can not deceive, harm, or ask your participants to eat or drink any substances You are not expected to conduct a ‘perfect’ experiment You are not allowed to replicate experiments about/using: conformity & obedience, animal research, placebo, ingestion, deprivation, young children, quasi experiments, questionnaires.

Step 2: Locating Sources Try to locate a copy of the original experiment on the internet Find at least 3 other related studies – RESEARCH! Analyze how all of these studies relate to your experiment – look at research design, findings etc Avoid too many internet sources. No Wikipedia!!!

Student Advice Do not underestimate the amount of time required to complete the IA Do not choose a study that is too obscure Scientific writing is “way harder” than you think Think about the best time to hold your experiment so that students will turn up Time management is the key!!!

Step 3 Modifying the Research Design You will have to modify the original experiment Sampling Reduce the number of variables Simplify the DV Use a different statistical test to determine significance

Step 3 Modifying the Research Design cont’ Independent measures design Vs. repeated measures design . (Be able to justify this in your report) Independent measures is usually best as you don’t have to undertake counterbalancing to avoid the test-retest confounding variable

Step 4 Obtaining your sample of participants Student body will be your target population It is best to select an opportunity sample but you will have to justify why you did this. i.e. easier, Ppts more willing An ideal sample is 50 students giving you two groups of 25. If you have some no-shows you will still have 20 per group

Step 4 Obtaining your sample of participants Signed informed consent forms must be obtained (You will provide a copy of the consent form in your appendix) Students younger than 16 will require parental consent You must keep all forms and ensure the confidentially of data You must collect relevant bio-data from the participants e.g. age, first language etc. You will report any relevant characteristics You must randomly assign participants to your groups!

Step 5 Ensuring Control The two groups in your experiment should be treated exactly the same except for the IV All instructions to the groups should be scripted to ensure they are identical All other conditions should be identical as far as possible; Room, time of day etc. Control for extraneous variables! Note any inadvertent differences in treatment and discuss this in your report

Step 6 Ethical Considerations Remind participants that they are free to leave the experiment at any time Debriefing: All participants must be informed of the results of your experiment

Step 7 Analyzing the Data – Descriptive Stats Use appropriate descriptive statistics (one measure of central tendency and one measure of dispersion) Present your data in both words and tabular form.

Step 8 Analyzing the Data – Inferential Stats Use non-parametric statistical tests of significance (Mann Whitney U-test) Your small sample size prohibits parametric tests like the t-test. Best to calculate your test yourself but double check with online sites Raw data and calculations should be included in the appendix

Which Inferential Test? HL only!! Level of measurement Appropriate test for independent samples Appropriate test for repeated measures Nominal (Categories, frequency) Chi-squared (X2 test) Ordinal, Interval or Ratio Mann-Whitney U test Wilcoxon signed ranks test

Writing Your Report You MUST follow the IB guidelines. Common omissions: no abstract; data not displayed in three ways i.e. words, tables and graphs; sources not cited, no Works Sited page; no appendices (sample informed consent form, raw data, statistical test calculations, scripted instructions) You must write like a social scientist. Avoid the 1st person “Basically I did this, then I did…..”