# Types of Errors

1. Two types of errors can be made in the test of hypothesis:
1. â€‹Type I Error:- the probability of committing type I error is P value. (AIIMS Novâ€™08 & Mayâ€™09)
That is the rejection of null hypothesis in spite being true
Also called as Alpha error. Q
Type I error = False positive error = P value
(Pneumonic: RNTCP = Rejecting Null Hypothesis when it is true. ANF accepting null hypothesis
when it is false)
2. Type II Error:- Beta Error Q
Accepting null hypothesis in spite being false.
Power (1-Beta) is defined as the probability of rejecting the null hypothesis when it is false. Normally accepted value for power is 80%. Levels of type I error are usually kept at or under 5%, the measure of alpha error is also called the â€˜pâ€™ value. Thus a â€˜pâ€™ value < .05 means the probability of getting a difference as extreme as; or more, given the fact that in reality no difference exists is less than 5%, in other words, the difference because of chance; is less than 5%.
â€‹â€‹Type II = Beta error = False negative error