PSYCHOLOGY IAPSYCHOLOGY IA

THE RESULTSTHE RESULTS

RATIONALE/PURPOSERATIONALE/PURPOSE

• The results section is where you The results section is where you report the results that you have report the results that you have found from your experiment.found from your experiment.

• You must report exactly You must report exactly whatwhat

you found, however you must you found, however you must not explain not explain whywhy you found it you found it here, this goes in the here, this goes in the discussion.discussion.

ASSESSMENT CRITERIAASSESSMENT CRITERIA

HL Criterion E - 2 marksHL Criterion E - 2 marksResults are clearly stated and accurate Results are clearly stated and accurate and reflect the hypotheses and and reflect the hypotheses and research. Appropriate descriptive research. Appropriate descriptive statistics are applied to the data and statistics are applied to the data and their use is explained. The graph of their use is explained. The graph of results is accurate, clear and directly results is accurate, clear and directly relevant to the study. Results are relevant to the study. Results are presented in both words and tabular presented in both words and tabular form.form.

HL Criterion F – 3 marksHL Criterion F – 3 marks

An appropriate inferential statistics test An appropriate inferential statistics test has been chosen and explicitly has been chosen and explicitly justified. Results of the inferential justified. Results of the inferential statistical test are accurately stated. statistical test are accurately stated. The null hypothesis has been accepted The null hypothesis has been accepted or rejected appropriately according to or rejected appropriately according to the results of the statistical test. A the results of the statistical test. A statement of statistical significance is statement of statistical significance is appropriate and clear.appropriate and clear.

THE ESSENTIALSTHE ESSENTIALS

• The essential elements of your The essential elements of your results section are as follows:results section are as follows:

• Descriptive statisticsDescriptive statistics (justification (justification of and explanation of)of and explanation of)

• The results table The results table (of descriptive (of descriptive statistics) statistics)

• GraphGraph (of descriptive statistics) (of descriptive statistics)• Inferential statisticsInferential statistics (justification of (justification of

and interpretation of)and interpretation of)

DESCRIPTIVE STATISTICSDESCRIPTIVE STATISTICS

• Your project must contain two Your project must contain two forms of descriptive statisticsforms of descriptive statistics

• 1) measures of central tendency1) measures of central tendency

- (i.e. mean/ median/ mode)- (i.e. mean/ median/ mode)• 2) measure of dispersion2) measure of dispersion

- (i.e. standard deviation)- (i.e. standard deviation)

MEASURES OF CENTRAL MEASURES OF CENTRAL TENDENCYTENDENCY

This includes the mean, median This includes the mean, median and mode.and mode.

You must first of all You must first of all justifyjustify why why you have chosen to use the you have chosen to use the mean, median or mode, i.e. mean, median or mode, i.e. what are the strengths and what are the strengths and weaknesses of them? Which is weaknesses of them? Which is the most appropriate? Why?the most appropriate? Why?

MEASURES OF CENTRAL MEASURES OF CENTRAL TENDENCYTENDENCY Then, you must include a table Then, you must include a table

of the calculated values of of the calculated values of mean, median or mode.mean, median or mode.

Do NOT Do NOT include your workings include your workings out here, they go in the out here, they go in the appendix (see appendix (see ‘‘additional additional important resourcesimportant resources’’). You can ). You can use a calculator.use a calculator.

MEASURES OF CENTRAL MEASURES OF CENTRAL TENDENCYTENDENCY

Then, you must Then, you must explainexplain what the what the calculated values show. This must calculated values show. This must be detailed, i.e. Use actual data in be detailed, i.e. Use actual data in your description. Are there any your description. Are there any obvious outliers in the results obvious outliers in the results table which may have distorted table which may have distorted the mean? Etc.the mean? Etc.

MEASURE OF DISPERSIONMEASURE OF DISPERSION

The appropriate measure of The appropriate measure of dispersion for interval/ratio data is dispersion for interval/ratio data is the standard deviation. This shows the standard deviation. This shows how spread out the data are from the how spread out the data are from the mean. mean.

You must first You must first justifyjustify why you have why you have chosen this. Hint! Look in the Course chosen this. Hint! Look in the Course Companion p398 for the conditions Companion p398 for the conditions under which the SD is used.under which the SD is used.

MEASURE OF DISPERSIONMEASURE OF DISPERSION Then, you must include the Then, you must include the

calculated value of the standard calculated value of the standard deviation for conditions A and B in a deviation for conditions A and B in a table. Put it in the same table as you table. Put it in the same table as you did for Mean/median or mode.did for Mean/median or mode.

Do NOT Do NOT include your workings out include your workings out here, they go in the appendix You here, they go in the appendix You can use a calculator or excel.can use a calculator or excel.

MEASURE OF DISPERSIONMEASURE OF DISPERSION

Then, you must Then, you must explainexplain what what the calculated value shows. the calculated value shows.

This must be detailed, i.e. Which This must be detailed, i.e. Which SD is larger? What does this SD is larger? What does this mean? mean?

THE RESULTS TABLETHE RESULTS TABLE

• You must include a table of You must include a table of results. results. Not raw data, this goes Not raw data, this goes in the appendices.in the appendices.

• Make sure you give a clear and Make sure you give a clear and detailed title.detailed title.

GRAPHGRAPH

You must display your results in You must display your results in an an appropriateappropriate graph. Only one graph. Only one graph is required.graph is required.

Make sure you give a clear and Make sure you give a clear and detailed title.detailed title.

LLaabel axes correctlybel axes correctly

INFERENTIAL STATISTICSINFERENTIAL STATISTICS

The appropriate measure of statistical The appropriate measure of statistical significance depends on:significance depends on:

1) Test of difference or correlation1) Test of difference or correlation 2) Level of data 2) Level of data 3) Whether the data is related 3) Whether the data is related (repeated (repeated

measures)measures) or unrelated or unrelated (independent (independent measures)measures)

It will either be a It will either be a Wilcoxon signed ranks Wilcoxon signed ranks test (repeated measures)test (repeated measures) or a or a Mann Mann Whitney U test (independent measures)Whitney U test (independent measures) depending on whether you have used depending on whether you have used repeated measures or independent groups repeated measures or independent groups respectively.respectively.

INFERENTIAL STATISTICSINFERENTIAL STATISTICS You must first You must first justifyjustify why you have chosen why you have chosen

your statistical test.your statistical test.

You need to explain the conditions under which You need to explain the conditions under which the test is used the test is used (Hint! This is explained on the (Hint! This is explained on the previous slide!).previous slide!). Data is Data is at least at the ordinal at least at the ordinal levellevel..

Working out can be done on the computer but Working out can be done on the computer but a printout must be provided. See booklet for a printout must be provided. See booklet for more detailed instructions.more detailed instructions.

INFERENTIAL STATISTICSINFERENTIAL STATISTICS

There are different levels of There are different levels of significance.significance.

The pThe p<<0.05 level is used as it is the 0.05 level is used as it is the conventional level of significance conventional level of significance that is accepted by psychologists.that is accepted by psychologists.

PP<<0.05 means that there is a 95% 0.05 means that there is a 95% chance that the results occur due to chance that the results occur due to an effect of the IV on the DV, and a an effect of the IV on the DV, and a 5% chance that the results occur due 5% chance that the results occur due to random variability.to random variability.

The The ‘‘pp’’ stands for stands for ‘‘probabilityprobability’’

INFERENTIAL STATISTICSINFERENTIAL STATISTICS

You must then You must then interpretinterpret your stats your stats test results using a test results using a ‘‘numerical numerical statement of resultsstatement of results’’. This should . This should include:include:

Calculated value (T (wilcoxon) OR U (Mann Calculated value (T (wilcoxon) OR U (Mann Whitney)Whitney)

Critical valueCritical value No. of Participants (N)No. of Participants (N) One tailed hypothesisOne tailed hypothesis Level of significanceLevel of significance Whether the null hypothesis is retained or rejected.Whether the null hypothesis is retained or rejected.

NUMERICAL STATEMENT NUMERICAL STATEMENT OF RESULTS EXAMPLEOF RESULTS EXAMPLE

The calculated value from the The calculated value from the Wilcoxon/Mann Whitney test was __. This Wilcoxon/Mann Whitney test was __. This is less than/ more than the critical value of is less than/ more than the critical value of __ for a directional/ non-directional (1 __ for a directional/ non-directional (1 tailed/ 2 tailed) hypothesis when N = __. tailed/ 2 tailed) hypothesis when N = __. This shows that the risk that this difference This shows that the risk that this difference occurred by chance is more than/ less than occurred by chance is more than/ less than 0.05 or 5%. The result is therefore 0.05 or 5%. The result is therefore significant/ non-significant and the null significant/ non-significant and the null hypothesis can be rejected/ retained.hypothesis can be rejected/ retained.