Textbook Notes (280,000)
CA (160,000)
SFU (5,000)
PSYC (1,000)
Chapter 4

PSYC 210 Chapter Notes - Chapter 4: Level Of Measurement, Central Tendency

Course Code
PSYC 210
Cathy Mc Farland

This preview shows half of the first page. to view the full 1 pages of the document.
PSYC 210
Measures of Central Tendency – numerical values that refer to the center of the distribution
Mode (Mo) – the most commonly occurring score
-if two nonadjacent values occur with equal (or near equal) frequency, we say that the
distribution is bimodal and would report both modes
orepresents the largest number of people having the same score
oapplicable to nominal data
onot sensitive to outliers
oMay not be particularly representative of the entire collection of numbers
Median (Mdn) – the score corresponding to the point having 50% of the observations below it
when the observations are arranged in numerical order
-median location = (N+1)/2
oUnaffected by extreme scores
oUseful in studies in which extreme numbers occasionally occur but have no
particular significance
oDoes not require any assumptions about the interval properties of the scale
oDoes not enter readily into equations
oNot as stable from sample to sample
Mean (X) – the sum of the scores divided by the number of scores
-equation = X =
oInfluenced by extreme scores
oValue may not actually exist in the data
i.e. data: 1,3, 8, 7, 14. X = 6.6
oits interpretation in terms of the underlying variable being measured requires at
least some faith in the interval properties of the data
oCan be manipulated algebraically
oStable estimate of the central tendency of that population
Trimmed Mean – the mean that results in the trimming away (or discarding) a fixed percentage
of the extreme observations
You're Reading a Preview

Unlock to view full version