RMA Week 7

variables

• something that varies

• A specific statement about how a variable will be measured to represent the concept under a study

measurement

a way to describe real life factors by numbers

operationalised

replicable, defined, quantifiable

scales

• used when operationalising a variable is more complex (e.g. liker)

• Nominal

• ordinal

• interval

• ratio

nominal data

labels, names, number

ordinal data

rank, order

interval data

gaps between scores all the same e.g. 10, 20, 30

ratio data

similarity with interval but described in ratios

number 0 = absence

only scale where 0 is meaningful

central tendency

• finding averages of data/ representations

• mena,median,mode

mean

add scores/ divide by number of scores

s/w - mean

s

incorparates all values of data

default measure

w

affected by outliers

median

middle score

• if 2 in middle (n+1)/2

s/w median

s

less affected by outliers( used instead of mean if scores extreme)

used for ordinal data

w

may not represent whole data set

mode

• count which score appears most commonly

• nominal data

s/w mode

s

useful for nominal data

w

• not a good representation of average affected by anomolies

• bi modal - two modes- not helpful for describing

• some data has no mode

• can be atypical