1. Unit 2 The Biological Approach
Evidence of Practice

2. Lesson outcomes
By the end of the lesson you will have completed the biological approach practical
You will have practised using psychological terminology
You will be ready to write up the practical over Easter

3. Practical: A test of difference
You need to be able to devise and conduct one practical, which must be a test of difference collecting ordinal or interval/ratio data using an independent groups design.
You should be able to carry out a Mann-Whitney U test and interpret the findings.
You should be able to write up the hypothesis, results and analysis of the study, using an appropriate graph and a table of the results, and to draw conclusions.

4. You must be able to... i alternative, experimental and null hypothesis
Identify, describe and apply the following terms:
i alternative, experimental and null hypothesis
ii one or two tailed with regard to tests
iii levels of significance (eg p= 0.01, 0.05)
iv Mann-Whitney U, - critical value and observed value
v dependent variable (DV) and independent variable (IV) in experiments
vi the use of control groups
vii experimental procedures including allocating groups to conditions (e.g. randomising) and sampling
vii levels of measurement.

5. Practical: A test of difference
Brain text book
Read pages in AS Psychology

6. Spatial Intelligence
Spatial intelligence is the ability to comprehend three-dimensional images and shapes. Visual spatial intelligence activities include putting together a puzzle or sculpture. This type of intelligence stems from the left side of the brain, and injuries or strokes to this part of the brain may diminish this ability. Spatial intelligences rely largely on people’s abilities to picture the shapes and spaces of objects in their minds; it is the ability to retain the form of something in the mind’s eye.

7. The highest visual spatial intelligences result from unique abilities to take up different positions in the mind’s eye, such as a fly on the wall or a person standing behind a curtain. Those who have high spatial intelligences usually do best in technical or science fields. Architects, navigators, chess players, physicists and designers are careers that people with high spatial intelligences are often drawn to.
Males are believed to have better spatial skills than females due to the way their brains are lateralised.

8. Conduct practical
Lets do it

9. Procedure - Methodoloy
Opportunity sample – AS psychology students
verbal consent obtained
Situational variables and ppt variables were controlled
Quasi/natural experiment
H1 – Males will achieve higher scores out of 33 on the psychometric spatial skills test than females

10. The experimental design was independent measures
Standardised instruction were used.
Ppts had 10 minutes – (timed with a stop watch) to complete the test.
The answer sheets were marked out of 33 and scores were collected.
The mean and median (measures of central tendency) were calculated and put into a table.
The means were then presented as a bar chart.
The range was calculated – the difference between the highest and lowest score for each group of ppts (males group and female group)

11. The range was calculated – this is the difference between the highest and lowest score for each group. This is called the measure of dispersion.
An inferential statistical test was then performed on the data. It was called the Mann-Whitney U test
This was the appropriate test as we were conducting an experiment. The level of data was ordinal (you can rank the scores from lowest to highest), and it was an independent measures design

12. The Mann-Whitney U test
Here is the formula

13. What were the results of your analysis from your Mann-Whitney U calculation?
Ua = ?
Ub= ?
The observed value of U is the Lowest number value of U (either Ua or Ub).
The Critical value for significance at 0.05 is the value we get from looking at the table.
If your observed value (the one we calculated) is lower than the critical value it means your results are significant at 0.05 or 5%. P≤0.05
Meaning: The probability of the results being a fluke (down to chance) is less than 5%
If your calculated U is higher than the critical value of U your results are not significant at 0.05 or 5%. P≥0.05.
Meaning: The probability of the results being a fluke (down to chance) is more than 5%

14. So we were required to use the lowest of the two values of U.
Ua was…..
Ub was……
So the observed value we used was ………….
The critical value from the Mann-Whitney U table was …………………….

15. If the result was significant we could reject the null hypothesis and accept the experimental hypothesis.
If it was not significant we had to reject the experimental hypothesis and accept the null hypothesis
The statement of significance was either
P≤ or P≥0.05

16. If your results are NOT SIGNIFICANT then you have to accept that any difference between the mean scores (as represented on your bar chart) are just a fluke! You have to accept the NULL hypothesis in this case 
The research was then evaluated using
G R A V E