Working with levels of significance

Match the following

• 1 in a 1000 results are chance

• 0.1% level of significance

• 1/100 results due to chance

• 0.5% level of significance

• 10 / 100 results due to chance

• 10% level of significance

• 5 in 100 results due to chance

• 5% level of significance

• 1 in 200 possibility

• 1% level of significance

Psychologists use a P<0.05 level of significance as it offers a (a)   between committing a type 1 and type 2 error.

A type one error is when we ______ the null although we should have _______

(a)  

A type two error is when we accept the (a)   hypothesis when we should have rejected it.

A type one error is when we:

• reject the alternative although we should have accepted it

• accept the alternative although we should have rejected it

• rejected the null although we should have accepted it.

• accepted the null although we should have rejected it.

A type two error is when we...

• reject the alternative although we should have accepted it

• accept the alternative although we should have rejected it

• reject the null although we should have accepted it

• accept the null although we should have rejected it.

A type one error is more likely to occur when the level of significance is...

• lenient

• stringent

• at a P<0.01 level than a P<0.1 level

• at a P<0.1 level than a P<0.01 level

A type two error is more likely to occur when the level of significance is...

• lenient

• stringent

• A P<0.01 level is used rather than a P<0.1 level

• A P<0.1 level is used rather than a P<0.01 level

Explain what the terms 'stringent' and 'lenient' mean when talking about levels of significance.

Which level of significance is the preferred choice for psychologists (write out as the probability fomula P< etc) and explain why?