Psych Stats Exam #1 Additional Info

Question 1

power

Answer 1

• compliment to or the probability of correctly rejecting the null hypothesis -> power = 1-β
• probability of type II error = β

Question 2

significance criterion (α)

Answer 2

• probability of type I error = α
  the smaller the alpha the more difficult it is to reject H₀, the lower the power

Question 3

sample size (n)

Answer 3

when all other things are equal, the larger the n the more the power
decreases probability of type II error
decreases the standard error of the mean

Question 4

effect size (d)

Answer 4

general measure of the effect or the degree to which the null is false
always positive
the larger the effect size, the smaller the n required to obtain significance

Question 5

retrospective power analysis

Answer 5

determine the power of a statistical test after it has been completed

Question 6

prospective power analysis

Answer 6

determines the necessary n to have some specific power, before the test has been done

Question 7

delta (δ)

Answer 7

an intermediate computation that combines info about effect size and sample size
use the power - looking at the criterion column

Question 8

point estimate

Answer 8

single guess
a compute statistic that estimates a parameter
the best single estimate of a parameter but is never exactly correct

Question 9

confidence interval

Answer 9

range of numbers that contain the actual number in it
on average sample mean is guaranteed to equal the estimated parameter but the point estimator could be quite discreapnt from the population parameter

Question 10

range

Answer 10

confidence level is 1-α
greater confidence level = greater probability interval will actually include μ