types of errors

• type I error

  'false positive'

  Accept the alternative hypothesis, deny the null hypothesis even though there was no difference.
• types II error

  'false negative'

  Accept the null hypothesis, deny the alternative hypothesis even though there was a difference.
• what type of error would psychologists prefer to make?

  Type II error.

  (saying that there is no difference when there is a difference is better than saying there is a difference when there is not)
• when are type I errors more likely to happen?

  When there is a high probability value (0.1/ 10% by chance).
• when are type II errors more likely to happen?

  When there is a low probability value (0.01/ 1% by chance).
• what is P = 0.05 good for?

  P = 0.05 caused by chance evens out the chance of both type I and type II errors.
• how do we avoid type I errors?

  Decrease the probability value.
• how do we avoid type II errors?

  Increase the probability value.
• how can we check if errors have been made?

  Repeat research with the same probability to see if we get the same results.