Measures of central tendency and variability

Reminders:

n: Count how many numbers there are


Mean: Add the numbers and divide by n


Degrees of freedom (df) (for variance): n-1


Variance:

  1. Subtract the mean from each number
  2. Square the answer
  3. Sum the squares
  4. Divide by the degrees of freedom

Standard deviation (s): find the square root of the variance

For each data set, find: n, mean, df, variance and standard deviation

Data 1: 10, 5, 7, 8, 3

Data 2: 25, 45, 80, 65, 73, 88, 91, 100

Data 3: 133, 145, 188, 215, 225, 250, 168, 212, 127



 

 

 

COM 582 Descriptive and Experimental Research in Communication

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