Numerical Descriptive Measures

is the extent to which all the data values group around a typical or central value

(a)  

is the amount of dispersion of scattering of values

(a)  

is the pattern of the distribution of values from the lowest value to the highest value.

(a)  

is the most common measure of central tendency

(a)  

X̄

(a)  

n

(a)  

Xi

(a)  

sum of values divided by the number of values

(a)  

Mean is affected by extreme values (outliers)

is the “middle” number (50% above, 50% below)