Psychology
Research methods
Correlation
Describe correlation
• A method used to assess the degree to which 2 co-variables are related
Strengths of correlation
• + Provides a means of looking at relationships between continuous variables and
determining whether relationship is significant.
• + Useful way to conduct a preliminary analysis on data
Weaknesses of correlation
• - Can't show cause-and-effect relationship as there is no IV that's been altered
• - There may be intervening variables explaining why the co-variables being studied
are linked.
Hypotheses
Describe directional (one-tailed) hypothesis
• States the direction of the hypothesis, like one condition is more useful than others
• Ppl who sleep for 8 hours have higher score on a memory test than those who sleep
for 5 hours
• IV increases/decreases DV
Describe non-directional (two-tailed) hypothesis
• States there is a difference. Can go in any direction
• Ppl who sleep for 8h perform differently on a memory test than those who sleep for
5h
• IV affects DV
Inferential stats
Inferential test decision tree
, 1. Difference or relationship
2. Nominal or ordinal data
3. Independent groups or repeated measures
Difference/ relationship and nominal data
Chi-squared test
Relationship and ordinal data
Spearman's rho test
Difference, ordinal data and independent groups
Mann-Whitney U test
Difference, ordinal data and repeated measures
Research methods
Correlation
Describe correlation
• A method used to assess the degree to which 2 co-variables are related
Strengths of correlation
• + Provides a means of looking at relationships between continuous variables and
determining whether relationship is significant.
• + Useful way to conduct a preliminary analysis on data
Weaknesses of correlation
• - Can't show cause-and-effect relationship as there is no IV that's been altered
• - There may be intervening variables explaining why the co-variables being studied
are linked.
Hypotheses
Describe directional (one-tailed) hypothesis
• States the direction of the hypothesis, like one condition is more useful than others
• Ppl who sleep for 8 hours have higher score on a memory test than those who sleep
for 5 hours
• IV increases/decreases DV
Describe non-directional (two-tailed) hypothesis
• States there is a difference. Can go in any direction
• Ppl who sleep for 8h perform differently on a memory test than those who sleep for
5h
• IV affects DV
Inferential stats
Inferential test decision tree
, 1. Difference or relationship
2. Nominal or ordinal data
3. Independent groups or repeated measures
Difference/ relationship and nominal data
Chi-squared test
Relationship and ordinal data
Spearman's rho test
Difference, ordinal data and independent groups
Mann-Whitney U test
Difference, ordinal data and repeated measures
