MEASURES OF CENTRAL TENDENCY Flashcards
1
Q
compressing mass of data for better comprehension and description
A
Summary measures
2
Q
- refers to “center” of the distribution of observations
most common measures:
* mean
* median
* mode
A
Measures of Central Tendency
3
Q
- sensitive to extreme observations
- involves all observation in its computation
- any change in the observation will change the mean value
- calculated for any quantitative variable
- unit is the same as that of the original set of observations
- sum of the deviations of the observations from the mean is equal to zero
- point of balance or center of gravity of the distribution
- serves as basis for the computation of higher statistical methods
A
mean
4
Q
- middle most value in a set of observations put in an array
- if odd: middle most observation
- if even: mean of 3 middlemost observation
A
MEDIAN
5
Q
- always exists and is unique
- not influence by outliers
- does not make use of all the observations in its computation
- can be calculated for any quantitative variable
- can be calculated for some qualitative variable
A
median
6
Q
- most frequently occurring value in a set of observation
- it is possible to have:
- no mode
- unimodal; bimodal; multimodal
- no calculations needed
- determined for any type of variable
A
MODE
7
Q
- gives information as to the tendency of values to clump together
- tools describing the variability of the observations
- homogenous
- heterogenous
- may be used for quantitative variables only
most common measures:
* range
* variance
* standard deviation
* coefficient variation
A
Measures of Dispersion
8
Q
- simplest measure of location
- formula
= highest observation – lowest observation - does not tell anything about the observation between these two extreme
observations - may be used for quantitative variables
A
RANGE
9
Q
- measure of variability that takes the mean as the reference point
- involves all observations
- unit: squared unit of the original set of observations
- hard to interpret
A
VARIANCE
10
Q
- square root of variance
- unit is the same as that of the original set of observations
- formula:
A
STANDARD DEVIATION
11
Q
- expresses the SD as percentage of mean
- most appropriate when:
- unit of measurement of variables being compared are different
- means being compared are markedly different
A
COEFFICIENT VARIATION
12
Q
measure of dispersion is high or large
A
heterogenous
13
Q
measure of dispersion is low or small
A
homogenous
14
Q
- determines the location/ position of particular value in an array of
distribution - provide more details about a part of the entire distribution of
observations in a give data - used for both qualitative and quantitative data
most common measures:
* quartiles
* deciles
* percentiles
A
Measures of Location
15
Q
- points of distribution that divides the observation into 4 equal parts
A
quartiles
