Probability and Significance

Created by

Alice Hadwen-Beck

Cards (10)

what is an experimental hypothesis?
makes predictions about the effect
what is probability?
a numerical value representing the likelihood of an event happening, measured on a scale of 0-1
what is significance?
a statistical term which indicates that the association between two (or more) variables is strong enough for us to accept the experimental hypothesis
what does 'p' represent?
the likelihood that the results are due to chance rather than the IV having affected the DV
0.05 probability level means we are sure we're 95% right
why do we have different probability and significance levels?
for precision, smaller probability level means greater chance that the results happened due to a real difference in our experiment rather than by random event
as significance levels increases, means there is a higher probability that results are due to a random event rather than a real difference in the experiment
in what scenarios would you use a 0.01 significance level?
studies which may affect human lives e.g. new drugs being trialled
When do we use a 0.1 significance level?

When a study is researching a new area where there is little established research, if results aren't significant, further research may not be carried out and the use of a less stringent significance level means that the chance of there being a real effect remains a possibility and isn't dismissed too quickly
what is a type 1 error?
rejecting a null hypothesis that is in fact true, we accept the alternative hypothesis when we should not because the results are due to chance
false positive - significance level is too high and lenient (thinking you've found something when you haven't)
what is a type 2 error?
accepting a null hypothesis when it is in fact false, we reject alternative hypothesis but we should not be because there was an effect which we have missed
a false negative - significance level is too stringent (thinking you've not found something when you have)