1
Q
Outline the difference between spearman correlation coefficient and Pearsons
A
Pearson
- calculated directly from the raw scores
- suitable for data on an interval or ratio scale
- highly affected by outliers
- not suitable for skewed data
Spearman
- calculated from the ranking of the raw scores
- suitable for data on an ordinal scale
- marginally affected by outliers
- suitable for outliers
2
Q
Outline density curves
A
- plots lots of people and lots of data
- area of curve is related to number of people, histogram curve
- displays overall, pattern of distribution
- calculated so they have an area of exactly 1 underneath them
Median= half of the area is below this point, half is above
Quartile= 25% of area is below Q1, 25% of area is above Q3
Mode= position at the peak of the curve
Mean= balancing point of the curve
3
Q
When you have a perfect curve (normal distribution), what is the relationship between the mean the median and the mode?
A
They are all the same value
4
Q
What is the relationship between the mean, median and mode when you have both positively and negatively skewed data
A
Positively skewed: mean is higher than the median, which is higher than the mode
Negatively skewed: mode is higher than the median which is higher than the mean
