probability & errors

• what is probability?

  is the likelihood that results are due to chance or not
• what indicates significance level?

  results need to be p<0.05
• what does p<0.05 mean?


  results are only 5% likely that they are due to chance

  we accept experimental hypothesis & reject null
• if results are not significant what do we do?

  accept the null hypothesis & reject experimental
• why might we want a significance level of p<0.01?

  would mean results are only 1% due to chance & we can 99% sure that its not

  far more likely that iv was affecting dv
• explain type 1 error?

  false positive

  accept experimental hypothesis & rejects null when they should not as results was due to chance
• why is false positive less likely to happen when its p<0.01?

  significant level is more stringent (strict)
• explain type 2 error?

  false negative

  reject experimental hypothesis & accept null when they should not as results were not due to chance
• explain 0.10?

  leads to type 1 error

  lenient significant level

  allows margin for error
• explain 0.01?

  leads to type 2 error

  stringent significant level

  no room for margin of error