Type I and Type II errors Flashcards

1
Q

how to control type I error

A

we control type one error when we choose the signifcance level

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1
Q

What is a type one error

A

Rejecting the null when it is true, this occurs when p<signficance level but the null is remains true. This can occur bc in a 95% confidance interval we are 95% sure that our value will fall within that interval however there is a 5% chance that the value falls outside of this value

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2
Q

What is type II error

A

Fail to reject the null when it is false , This may occur as there are times when the null is false however we do not have the evidance to spport it

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3
Q

what causes type II error

A

our sample size and study design, a larger sample size should limit type II error

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4
Q

what is POWER

A

1-P(typeII error) High powers make it easier to reject a null, low powers make it more challnaging

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5
Q

mutplie comparisons

A

Suppose the null is true. We still have a 5% chance of rejecting a true null, and therefore a 95% chance of correctly not rejecting it.
If we have two nulls, both of which are true, then the probability that we correctly don’t reject either is 0.95*0.95 = 0.9025. This means we have a 9.75% chance of rejecting at least one of them, even though they’re both true.
The multiple comparisons problem states that, when we check a lot of p-values, the Type 1 Error increases.

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