# Mean, Median, and Mode

• Sometimes you get very similar results with all three.
• Like when you have a normal distribution.

# Mean

#### 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.

# Median

• Use the median when you have extreme you have extreme scores or a skewed distribution

# Median

• 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 .

# Median

• In psychology, you might encounter an open-ended distribution like this:
• N = 20
• Cannot compute a mean.
• Median = 1.5
• Use the median!

# Median

• 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

# Mode

• Use the mode if you have nominal data
• Example:
Hair color: 1= brown , 2 = black , 3 = blond 4 = red

N=18

# Mode

• 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.”