Descriptive Stats Flashcards
What do measures of central tendency do?
Inform researcher about the performance of ppts in a group using a number of
What are the 3 examples of measures of central tendency:
- Mean
- Median
- Mode
How to calculate mean:
Add up all ppts scores and divide by number of scores there are
Strength of mean:
+ more representative as it takes all ppt scores into account rather than focusing on just one value
Weakness of mean:
- as it takes all ppt scores into account, can be affected by anomalous results
Interpretation of mean:
Higher mean suggests better performance. There are exceptions to this for example reaction time, number of errors, depression score
What is standard deviation?
Tells us how far each ppt value is from mean.
What does a high standard deviation tell us?
More variation/ spread away from the mean and less consistency around the mean
What does a low standard deviation tell us?
Less variation/ spread away from mean, more consistency around the mean
Two strengths of finding the standard deviation:
+ as it takes into account every ppts score, it is more representative
+ since it measures the distance of each score from the mean, it is only slightly affected by anomalous value if there is one
What is range?
Largest value - smallest value
What does high range tell us?
More variation and spread + less consistency in ppt scores
What does low range tell us?
Less variation and spread + more consistency in ppt scores
Two weaknesses of finding the range:
- since anomalous results will always be the highest or lowest value, range is skewed by outliers
- since focuses on highest and lowest values - not representative as it does not take all ppts performances into account
