Rafiq uses a non-directional (two-tailed) hypothesis
Explain whether Rafiq’s data were significant at p<0.05 and if the research hypothesis should be accepted
- the critical value is 0.786 at 0.05 for a two tailed test when n=7 which is more than the calculated value (of -0.0625)
- so there’s no significant relationship between age and number of hours of sleep, + the null hypothesis should be accepted
Nadia and Tamal use Spearman’s rho to analyse their data.
State two reasons why they use spearman’s rho
- they are looking for a correlation
- because they have ordinal data
Describe how Lauren could use a correlational research method to investigate whether aggression could be related to hunger
- Lauren could put posters around the uni campus which asks students to take part in a study for how aggression is related to hunger to gather a volunteer sample
- use self-rated aggression levels in the past month whereby 0=low and 10=high
- use self-rated hunger levels in the past month whereby 0=not hungry and 10=very hungry
- plot co-variables of aggression and hunger on a scatter graph to see if there’s a significant correlation
Define positive and negative correlation
Positive - show that as one variable increases the other variable increases
Negative - show that as one variable increases the other decreases
Strength + weakness of correlational research method
Strength - allows researchers to investigate naturally occurring variables (1) that may be unethical or impractical to test experimentally in a lab (1)
Weakness - cannot establish a cause and effect relationship between variables (1) as there may be a lack of control over the other variables (1)
Two reasons for using fMRI scan
- Amanda’s doctor may consider an fMRI scanner can show good spatial resolution of potential aggressive brain areas (1) which could provide valid identification of areas of Amanda’s brain that might be involved in her aggression
- Amanda’s doctor may consider that fMRI is non-invasive method of looking at aggression in her brain (1) which is ethically more acceptable than sending Amanda for surgery or any other form of invasive treatment (1)
Determine the lowest level of significance Oscar could use for his results to be significant for a directional hypothesis
To be significant, p=0.025 is the lowest level of significance Oscar can use for a one-tailed test (where N=8) (1) as Oscar’s calculated value (0.792) will still exceed the critical value (0.738) at this level
