How do we calculate our measures of central tendency?

• Mode: Find the value of the score with the highest frequency.
  
  
• Median: Find the value of the score that divides the distribution in half with 50% of scores above the median and 50% below the median.
  
  
• Mean: Take all the scores, add them up and divide by the total number of
  scores (N).
  Formula: (Sum of X/N)

Additional things to know:

• The mean is the center of normal distributions.
• For skewed distributions - report both the mean and median.
• For normal distributions - the mean, median and mode are equal.
• The mean is unbiased – on the average, sample means aren’t always too high or too low.

Where are we now!
We now can make a frequency distribution and calculate three different measures of central tendency. Now we need measures of variability.