Practical Investigation

Question 1

What is the aim of the practical?

Answer 1

To investigate if there is an association between height and self-rated levels of aggression.

Question 2

What is the one-tailed alternative hypothesis?

What is the null hyppthesis?

Answer 2

There will be a relationship between height (in centimetres) and levels of aggression (out of 30 on an aggression questionnaire).

There will be no significant correlation between height (in cm) and self-reported levels of aggression (on a scale of 1-5 out of 30) on an aggression questionnaire. Any correlation found will be due to chance.

Question 3

What are both the co-variables?

Answer 3

Height, measured in cm.
Self-reported aggression levels, measured by a scale of 1-5 out of 30.

Question 4

What is the procedure?

Answer 4

Standardised questionnaire, objective measurement of height, objective measure of aggression from 1-5, scales reversed to ensure attention.
An opportunity sampling method was used of DRHS sixth form female students present in the group study room in a free period.
20 female sixth form students, aged 16 to 18.
Informed consent from pps.
standardised questionnaire to each participant.
Each pps was read the same instructions asking them to complete the questionnaire without discussion with anyone else.
The questionnaire asked their height in cm and for them to rate on Likert scale of 1-4 how far they afree with 6 statements on aggression.
PPs given an aggression score out of 30.

Question 5

Describe the questionnaire.

Answer 5

1 question on their height in cm.
Rate each statement from 1 (strongly agree) to 5 (strongly disagree).
EG: I get angry is my friends overrule my suggestions, smallest things make me angry, i tend to laugh things off, i resort to shouting if I feel I’m not being listened to.

Question 6

What ethical issues were considered?

Answer 6

One ethical consideration was protection of participants. I avoided use of distressing life events such as death of a loved one to avoid causing any psychological harm following the BPS ethical principle of responsibility.
Consent form provided and debrief form provided outlining the true aim, participants reminded of their right to withdraw, participants’ data kept anonymous and confidential.

Question 7

What were the results?

Answer 7

I conducted a Spearman’s Rho test because I was investigating a correlation between 2 co-variables (height and aggression) and the level of data was ordinal (height in cm and aggression level out of 5).
The calculated value (0.992) was greater than the critical value (0.380) using a one-tailed test at p<0.05. This means we accept our alternative hypothesis and reject our null hypothesis, at a confidence level of 5%.
We can be at least 95% confident that there is a significant positive correlation between height in cm and self-rated aggression on a scale of 1-5.
The correlation coefficient value was 0.992, this means there is a strong positive correlation.

Question 8

What is the conclusion?

Answer 8

In conclusion, there is a significant positive correlation between height in cm and self-rated aggression on a scale of 1-5.

Question 9

What are 2 improvements i can make to this investigation?

Answer 9

I could complete a pilot study for my self-report questionnaire asking five students to complete the questionnaire before giving it out to my sample group which would eliminate any design flaws surrounding my questions on aggression and height as I could identify any ambiguous or unclear questions and change them before giving the questionnaires to the sample population.

I could increase the variety of people who answered the questionnaire on height and self-rated aggression by asking male students as well as female students from a range of different types of school sixth forms which would increase the generalisability of the sample used so it was more representative of both males and females and students of different educational levels and how they self-rate their aggression.

Question 10

Describe the weakness of generalisability.

Answer 10

Participants used were 16-18 year old females from a grammar school, who are likely to have much lower levels of testosterone than males which means the sample is less representative of males aged 16-18 who will have an increase in testosterone increase during the teenage years meaning the results cannot be generalised to males, people of different age groups or educational levels.

Question 11

Describe the strength of reliability.

Answer 11

My correlational study into height and self-rated aggression was controlled using the same questions for everybody so it can be tested for reliability because I can replicate the study multiple times to check for consistency in the results about height and aggression.

Question 12

Describe the strength of applicability.

Answer 12

If a correlation is found, early intervention can be put into place for those deemed “susceptible” to become aggressive, by partaking in cathartic activities such as sport.

Question 13

Describe the strength of validity.

Answer 13

By getting the sixth form students to fill in the self-rating aggression questionnaire themselves validity would be increased as they were more likely to write down realistic answers to the aggression questions than if they had to provide verbal answers to an interviewer as they may have been embarrassed.

Question 14

Describe the weakness of validity.

Answer 14

The measure of aggression was self-rated which may have been biased as the answers provided by the gym members may not have been realistic as they could have provided answers that did not reflect their true aggressive behaviour as they wanted to show social desirability and hide their true aggressive tendencies.

Question 15

Describe the strength of ethicality.

Answer 15

All guidelines by the BPS code of conduct were followed. Participants were given the right to withdraw and provided informed consent for their participation. Participants were fully debriefed at the end of the procedure. No psychological harm was caused as questions were chosen carefully to avoid distressing life events.