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Flashcards in lecture 5 Deck (7)
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1
Q

what is the procedure for inferential statistics

A
  1. hypthesis
  2. significance level: decide on it –> use 0.05
  3. sample: take a sample from the population
  4. p value: done by a computer –> this is the use of a test like t and chi squared
  5. decision has to be made
2
Q

what is a type 1 error

A

when you reject a true null hypothesis, also called false positive, the probability of type I error is just 𝛼, the significance level or size of test chosen

3
Q

what is a type 2 error?

A

when you accept a false null hypothesis, also called false negative, the probability of making this error is denoted by 𝛽-depends on the sample size and the population variance

4
Q

what is the formula to find β€˜z’

A

B hat/ SE(Bhat) = p value

5
Q

what is the β€˜power’ f a test?

A

power = 1 - Pr(type 2 error)

stricter the test then the lower the power is

cant attach a specific number to a test but they can be ranked

e.g.
if the tail had an area of 0.088 (5% part), then power = 1-0.088=0.912

6
Q

what is the formula for the z transformation to derive a confidence interval for a slope co-efficient?

A

Bhat-B/(varience/ E(X-Xbar)^2

7
Q

if you can derive the SE of the intercept, what can you base the tests aroung

A

Bhat-Bbar/SE(Bhat)

you can do this with the intercept as well (a)