Inferential Statistics

what are the three factors used to decide which stats test to use in research?

test of difference or correlation, experimental design, type of data

when would a sign test be used by a researcher?

test of difference, repeated measures or matched pairs, nominal data

why might assign test be considered less powerful than another stats test

nominal data which is the least powerful unreliable

how do you calculate S

• subtract one value from the other and place in difference column

• count the number of positive and negative signs

• which have a number is smaller becomes observed value S for the test

how do you identify a critical value

• check whether test is directional (one tailed) or non directional (two tailed)

• select correct level of significance

• Find the value N which is the number of participants

what is type 1 and type two errors

Type 1

• False positive

• wrongly accepted hypothesis rejected null hypothesis have said something is statistically significant when it isn't

• Type 2

• false negative and opposite