1. Writing the IA Report: Analysis and Evaluation
IB Diploma Psychology

2. Analysis: What you need to do.
Display your data with a table and graph
Provide the raw data and the calculations in the appendices
Use descriptive statistics to highlight the variability of your data (mean, median or mode) and the spread of data (Range or SD).
Use inferential statistics to draw a conclusion about your Research Hypothesis.
Your Analysis
(6 marks)

3. Analysis: How to Reach the Top Mark Band
Descriptive and inferential statistics are appropriate and accurate
The graph is correctly displayed and addresses the hypothesis
The statistical findings are interpreted with regard to the data and linked to the hypothesis
Grade of 5-6

4. Analysis: How to Reach the Top Mark Band
Descriptive statistics are appropriate and accurate
State one measure of central tendency (mean median or mode)
State one measure or spread (range of SD)
Explain why your measures are appropriate for the data you have collected
Explain what the tests show
Resources:
Scales of measurement
Central Tendency

5. Analysis: How to Reach the Top Mark Band
Inferential statistics are appropriate and accurate
State the test you used and why it was appropriate
Provide raw data and screenshots in the appendices
State the results
Reject the null hypothesis or not
Accept the Research hypothesis or not
State the level of significance
Resources:

6. Analysis: Determining appropriate statistics
Median and Range
Mann-Whitney U Test
Ordinal Data
Independent Measures
Signed Ranks Test
Repeated Measures
Mean and SD
Interval or Ratio
Mean and SD
Wilcoxon Signed Ranks Test
You will need to explain you decisions about what descriptive and inferential statistics you to analyse the data. The decision about the measure of central tendency is related to the type of data your have.
The decision about the spread is generally linked to the measure of central tendency you used. If you have used the median as you measure of CT then the range is the most appropriate measure of spread. If you are able to calculate a mean then the SD is the most appropriate measure of spread.
One of our teachers who is an IA examiner provide this general rule:
If an independent samples design was used, then the Mann Whitney U test can be applied to test the significance of the difference between two conditions.
If a repeated measures design was used, then the Wilcoxon Signed Ranks test: can be applied to test the significance of the difference between the two conditions.  If in doubt about whether to use the t-test or the Wilcoxon Signed Ranks test, you can use the Wilcoxon Signed Ranks test for any test of difference of two dependent groups.
The Chi-Squared test is used for nominal data in an independent samples design. 
The thinking behind the use of the Mann Whitney U test and not the more “powerful” t-test is that your data is not fully meeting the requirements for the t-test as your target population is unlikely to be normally distributed and your sample is probably small. You may have outliers which indicates that you data is not suitable for a parametric test. .
You need to state in your report that you are assuming your data does not meet the requirement of the t-test therefore the Mann-Whitney U test was used.

7. Analysis: Statistical Calculations
This site is helpful in choosing the appropriate test, put in your data, and the site does it for you. Make sure you check the correct box for one­  or two-­tailed hypothesis.
 ­ Free online calculation of your statistics. 
 ­ Useful site for choosing the right statistical test.
Click on ‘Ordinal Data’ to find the Wilcoxon and Mann­ Whitney tests.
You will need to explain why you use the tests. The decision about the measure of central tendency is related to the type of data your have.
The decision about the spread is generally linked to the measure of central tendency you used. . If you have used the median as you measure of CT then the range is the most appropriate measure of spread. If you are able to calculate a mean then the SD is the most appropriate measure of spread.
One of our teachers who is an IA examiner provide this general rule:
If an independent samples design was used, then the Mann Whitney U test can be applied to test the significance of the difference between two conditions.
If a repeated measures design was used, then the Wilcoxon Signed Ranks test: can be applied to test the significance of the difference between the two conditions.  If in doubt about whether to use the t-test or the Wilcoxon Signed Ranks test, you can use the Wilcoxon Signed Ranks test for any test of difference of two dependent groups.
The Chi-Squared test is used for nominal data in an independent samples design. 
The thinking behind the use of the Mann Whitney U test and not the more “powerful” t-test is that your data is not fully meeting the requirements for the t-test as your target population is unlikely to be normally distributed and your sample is small and there is the presence of outliers.
You need to state in your report that you are assuming your data does not meet the requirement of the t-test therefore the Mann-Whitney U test was used.

8. Evaluation: What you need to do
Relate your results to the results of the original study/theory/model cited in the Introduction (and remember to cite them again).
State and explain the strengths and limitations of your design, sampling, procedures, and overall methods.
Suggest and justify modifications that are explicitly linked to the limitations.
Provide a conclusion.
Your Evaluation (6 marks)

9. Evaluation: How to Reach the Top Mark Band
The findings are discussed with reference to the background study, theory or model
Strengths and limitations of the design, sample and procedures are stated and explain an relevant to the investigation
Modifications are explicitly linked to the limitations of the students investigations and fully justified.
Grade of 5-6

10. Evaluation: How to Reach the Top Mark Band
The findings are discussed with reference to the background study, theory or model
Do your results support or refute the findings of the original study? Explain why or why not?

11. Evaluation: How to Reach the Top Mark Band
Strengths and limitations of the design, sample and procedures are stated and explained and relevant to the investigation.
Identify and explain strengths and limitations.
Remember a mistake on your part is not a limitation.
Identify confounding variables and how you tried to control for them.
Was your random allocation or counterbalancing effective? Explain why or why not?
How ecologically valid was your study?
Did your sampling enable you to generalize your findings?

12. Evaluation: How to Reach the Top Mark Band
Strengths and limitations of the design, sample and procedures are stated and explain an relevant to the investigation
Key term:
Participant variability
Experimenter bias
Expectancy effect (demand characteristics)
Control

13. Evaluation: How to Reach the Top Mark Band
Modifications are explicitly linked to the limitations of the students investigations and fully justified.
Aim for three or four modifications that are directly linked to your limitations.

14. Evaluation: How to Reach the Top Mark Band
Modifications are explicitly linked to the limitations of the student’s investigations and fully justified.
What could you control more effectively?
How could you improve the procedures?
How could you deal with the expectancy effect?
Who could you make you study more ecologically valid?
How could you improve the generalizability of the study?