Mean, Median, and Mode
- Sometimes you get very similar results with all three.
- Like when you have a normal distribution.
Usually, the mean is preferred:
- It uses all the scores ( so it’s representative of the entire data set ).
- It’s used to compute the variance and SD.
- It’s good for inferential statistics.
- Note that you should have interval or ratio data to compute a mean.
- Use the median when you have extreme you have extreme scores or a skewed distribution
- Use the median when you have extreme scores or skewed distribution.
- Example :
- X = 10, 11, 11, 11, 11, 12, 12, 13, 13, 100
- M = 20.3
- Median = 11.5
- Median represents most of the distribution best .
- In psychology, you might encounter an open-ended distribution like this:
- N = 20
- Cannot compute a mean.
- Median = 1.5
- Use the median!
|Number of Children||Frequency|
|5 or more||32|
- Use the median if you have ordinal data
- Remember, the mean balances distance
- With ordinal data, you don’t have equal distances between data points
- Use the mode if you have nominal data
Hair color: 1= brown , 2 = black , 3 = blond 4 = red
- If you have a discrete variable like a number of children, you can compute a mean.
- In this case, means are fractional values that can’t really exist. EXAMPLE: “The average family has 2.5 kids”
- The mode identifies the typical case: – “The typical family has 2 kids.” – “The modal age for spinal cord injury is 19.”