MEANThe average of the data set.

Population:

Sample:

N

x

n

xx

MEDIANThe middle number after they

are put in order

MODEThe number that occurs most

often.

Mode:7

BIMODALWhen the data set has more

than one mode

INNER QUARTILE RANGEThe range between Q1 and Q3

OUTLIERA data entry that is far

removed from the other entries in the data set.

WEIGHTED MEANThe mean of a data set whose entries have varying weights.

SOURCE SCORE, x WEIGHT, w xw

Test Mean

Midterm

Final

Computer Lab

Homework

86

96

82

98

100

0.5

0.15

0.2

0.1

0.05

43

14.4

16.4

9.8

5

6.88 wx1w

w

wxx

MEAN OF FREQUENCY DISTRIBUTION

Finding the mean of grouped data. Where x and f are the

midpoints and frequency of a class

N

fx

n

fxx

SYMMETRIC DISTRIBUTIONWhen a vertical line can be drawn

through the middle of the graph and the resulting halves are approx.

mirror images                             

UNIFORM DISTRIBUTIONWhen all entries or classes have

equal frequencies

SKEWED RIGHTA distribution where the tail

extends to the right. (Positively Skewed)

SKEWED LEFTA distribution where the tail

extends to the left. (Negatively Skewed)