`RMA - Week 11

probability (p)

a measure of how likely it is that an event will occur

null hypothesis

• assume the … is true

• (no difference found)

• under this assumption calculate how probable it is to get a score as extreme or more extreme than what was obtained

reject null

• probability of of getting a score more extreme or of same extremness of what was obtained is very low then…

accept null

• if probability of getting a score more extreme or of same extreme is not small then…

threshold of rejection of null

5% or p=0.05

so if p = <0.05…

accept alternative

critical values

• Real-life scores that are the threshold for statistival signidicance

• scores above threshold significantly higher than general population scores

• scores below one threshold signfiicantly lower than population scores

type 1 error

rejecting null when we should accept it

deciding score is significant when it is not

significance is wrongly found 5 times out of 100 (0.05)

Type 2 error

• failing to reject null when we should

• findign a score to be not significantly different when it is

• decreasing type 1 chance increases chancew of this

directional hypothesis - one tailed

Predicts both that an effect exists and the direction of that effect (e.g., higher, lower).

non-directional (two tailed)

Predicts that there is a difference, but does not specify the direction.

Alternative hypothwsis

• States that there is an effect or a difference in the population.

• Opposes the null

statsitical inference logic

• cant be fully sure we are testing true zero score as we are only testing a sample of the whole population

• use probability theory to make inferences

• genrewalise to the whole target population