Central Tendency Flashcards
What is mean?
The average (sum of all scores divided by the total number of scores)
Used for subsequent calculations of statistical inference
What is median?
The 50th percentile
What is mode?
Most frequent score
How to calculate mode?
No formula
- rank order look for score that most frequently occurs
- simple/grouped distribution look for highest score in the frequency column
There can be more than 1 mode
Mode disadvantages
- Unstable: may change depending on methods of grouping
- Terminal statistic: not useful for further calculations
- Ignores extreme scores
What is the most sensitive central tendency?
Mean, because it’s affected by every score in a data set
Outliers have a greater effect on the mean
How to calculate mean
mean = sum of all scores / total number of scores
Relationships between mean, median and mode
- When data are distributed normally, the three measures of central tendency all fall at or near the same value
- When data is skewed, these values are no longer identical
Use mode if…
Only a rough estimate of central tendency is needed and the data is nearly normal
Use median if…
- the data is an ordinal scale
- A middle score is needed
- most typical score is needed
- curve is badly skewed by extreme scores
Use mean if…
- data is near normal
- further calculations
