Definisjonsdeck

Question 1

P-verdi

Answer 1

P-verdi sier kun noe om sannsynligheten for at en observert sammenheng/forskjell skyldes utvalgstilfeldighet.

In null-hypothesis significance testing, the p-value[note 1] is the probability of obtaining test results at least as extreme as the result actually observed, under the assumption that the null hypothesis is correct.

Question 2

Power

Answer 2

Sannsynligheten for å oppdage en forskjell hvis den faktisk er der.

A probability that a test of significance will detect a deviation from the null hypothesis, should such a deviation exist. For example if your power is 80% there is a 80% chance that your test will reveal a significant difference, given that it exist.

Question 3

Type I error

Answer 3

Type I error: to reject the null hypothesis when it is true. The p-value is the probability that you make a type I error if you reject the null-hypothesis.

Question 4

Type II error

Answer 4

Type II error: to accept the null hypothesis when it is false. Power is the probability of avoiding a type II error.

Question 5

Hvordan er sammenhengen mellom power og type II error?

Answer 5

Power is the probability of avoiding a type II error.

Question 6

Hvordan er sammenhengen mellom p-verdi og type I error?

Answer 6

P-verdi er sannsynligheten for å gjøre type I error

Question 7

Hvilke fire faktorer påvirker power?

Answer 7

1 Effect size
2 Standard deviation of the characteristics du undersøker
3 Sample size
4 Signifikanslevel