3. Probability, Type 1 And 2 Errors

Question 1

What is a type I error ?

Answer 1

• This is where we wrongfully accept the experimental hypothesis. This means we believe there is a difference or relationship, when actually no such relationship exists. This is sometimes known as a false positive or an error of optimism
• the less stringent the significance level the more likely it is we make a type I error

Question 2

What is a type II error?

Answer 2

• This is where we wrongfully accept the null hypothesis. This means we believe there is no difference between conditions or no relationship when in-fact a relationship does exist. This is sometimes known as a false negative or an error of pessimism
• the stricter the significance level the more likely it is we make a type II error

Question 3

What error is more likely when we use p<0.01 and why?

Answer 3

• Type II

- the area is stricter

Question 4

What error is more likely when we use p<0.10 and why?

Answer 4

• Type I

- the area is less strict