PSY201H1: Chapter 4 Review Notes
- A characteristic of frequency distribution and its derivatives would be that it
does not allow quantitative comparisons to be made between two or more
- The measure computed (of the average score of each variable) is a measure
of the central tendency of each distribution.
- It is important and useful to quantify the variability of the distribution.
- Central tendency and variability are the most important factors, and the two
characteristics of distribution which are typically quantified.
Measures of Central Tendency
- Value originally calculated when you average something.
- The sum of the scores divided by the number of scores
- Key properties of the mean include the fact that it is sensitive to the exact
value of all the scores in the distribution. Any change in the scores will cause
a change in the mean.
- The sum of the deviations about the mean equals zero. Algebraically:
- The mean is also very sensitive to extreme scores (Extreme scores: Score that
is far from the mean score)
- The sum of the squared deviations of all the scores about their mean is a
- Of the measures used for central tendency, the mean is least subject to
- Often known as the weighed mean.
- Typically represented algebraically as: Median
- Defined as the scale value below which 50% of the scores fall.
- The median is the centermost score if the number of scores is odd. If the
number is even, the median is taken as the average of the two centermost
- The median is also