correlational study involving a stroop test Flashcards
What are the covariables you’re assessing?
- How quickly someone can complete a Stroop test accurately
- Academic ability using their GCSE scores.
State the operationalised experimental hypothesis
There will be a negative correlation between the time it takes to complete the Stroop test and their academic ability
Identify if your experimental hypothesis is directional or non directional
Directional.
Justify why you chose to use a directional or non directional hypothesis
There’s plenty of scientific evidence to support the link that people with higher IQs resolve Stroop tests better (Duan and Shi 2011). So it’s reasonable to believe that those with higher GCSE will be better.
State an appropriate null hypothesis
There is no significant correlation between the time it takes to complete a Stroop test accurately and the academic ability of an individual.
Identify the main characteristics of your sample group
Number: 26.
Gender: 17 females, 9 males.
Other features: all participants are 18yr old A level students, none of which study psychology.
Identify the sampling method you employed to select your sample.
Volunteer/self selected. Notice placed on sixth form common room stating two variables that were measured. Volunteers responded by email and were given a lollipop and told data was confidential with right to withdraw.
Explain two advantages of your choice of sampling technique
- Less ethical issues because the participants came to us knowing the details of the study and understood their ethical rights from reading details.
- Volunteer samples have low dropout rate, since stroop can be quite stressful volunteer students would be unlikely to dropout.
Explain two limitations of your sampling technique
- Participants don’t represent everyone in society, as they knew the variables were people with good GCSE scores more likely to volunteer.
- Volunteer sample are more likely to perform better at stroop test because they have volunteered to take part so don’t want to let the study down.
Step by step description of your procedures
- volunteer sample collected.
- each participants stroop test time and capped 9 GCSE score placed next to each other on the excel spreadsheet but no further data collected so no participant identified.
- everyone who did the Stroop before was withdrawn, ask age and let them read consent form. Details collected and signed form.
- on school laptop opened faculty of Washington Stroop test page where under guidance and quiet environment they did it.
Identify an appropriate descriptive statistic that could be used to describe the data collected
Mean as measure of central tendency, then standard deviation to see the spread of the stroop test scores and capped nine GCSE scores to see if they followed normal distribution
Explain why your choice of descriptive statistic is appropriate
None of the GCSE capped nine scores or Stroop test score were extreme scores that would affect the mean. This was shown in the fact that both sets of scores showed normal and not skewed distribution.
Identify an appropriate graphical representation that could be used to describe the data collected
A scatter graph to see if there is a relationship between the participants capped nine GCSE score and their successful Stroop test time.
Explain why your choice of graphical representation is appropriate
- A scatter graph is the only graphical method of visually demonstrating if there is a correlation between GCSE capped 9 scores and Stroop test scores.
- Enables quick and clear representation of the GCSE and Stroop test score to see if there is an obvious correlation between the two co variables.
Identify an appropriate inferential statistic that you used to display the data collected.
Spearman’s Rho
Explain why your choice of inferential statistic is appropriate
We needed to find the direction and strength of the relationship between two variables. The data we collect on the two covariables is numerical. GCSE scores is a numerical value with a maximum of 90 and Stroop test measured as time in seconds.
Briefly summarise your findings
Spearman’s Rho score= -0.45
N=26
A critical value with a directional hypothesis when N is 26 at probability 0.05 is 0.259, so as our score of -0.45 is further away from the 0 and in the same direction as the experimental hypothesis predicted. We can accept the experimental hypothesis.
What conclusions can you draw from these findings
We can accept the experimental hypothesis as our score of -0.45 is further away from the 0, as our experimental hypothesis predicted.
There will be a negative correlation.
This shows student that have higher GCSE scores perform significantly better at Stroop test.
Identify two issues of reliability you faced in your research
- Inter-rater reliability between researchers as some may be better at recognizing mistakes and getting participant to go back.
- Internal reliability as performance on first part of Stroop may be better than end
How did you establish inter-rater reliability was reliable
To deal with differences of researchers, classroom based training was held in advance where a common script was formulated and training.
How did you establish internal reliability was reliable
The split half technique was done to test internal reliability. Timed each other performing first and second half of Stroop. Times similar.
Identify two issues of validity faced in research
- Self serving bias as participants may lie about GCSE scores.
- Concurrent validity as the one used may not be valid as it may be short or unclear compared to more established Stroops.
Explain how you established content validity was valid (that there wasn’t self serving bias)
GCSE scores were checked to ensure they were accurate, as stated by participant.
How did you ensure concurrent validity
In a pilot study, psychology students compared their score on the stroop test used with other more established tests and found that they compared well.
Identify two ethical issues that concerned you before the research
- Lack of confidentiality as their scores may embarrass them.
- Not saving participants from harm as performing Stroop badly could cause stress.
Explain what you did to deal with the ethical issue of ensuring confidentiality
Informed consent explained in detail that their data on GCSE score and Stroop was confidential and added anonymously to excel
Explain what you did to deal with the ethical issue of not saving participants from harm (stress)
In the infromed consent it explained in detail that Stroop was challenging and stressful and that they could leave the study at any time and remove data. This was repeated at end of investigation. Stop study if stressed but this didn’t happen.
Explain two ways you could improve your research
- Self selecting sample method meant only those that liked performing cognitive tasks and those happy with GCSE results took part so biased sample. Could change to random sample.
- To improve external reliability we could have used test restest on Stroop to measure their stroop time more than once over weekly period
Why use a correlation study
It’s impossible to manipulate the variable intelligence. It can only be measure
Why not use a correlation study
No cause or effect relationship so can’t say which variable causes the other
What kind of location was this test
Field experiment (we went up to the person with Stroop test)
Positive of field experiment
More natural, less stress. External validity
Negative of field experiment
Can’t control extraneous variables.
