Module 4 Flashcards
Type 1 error
the rejection of a true null hypothesis
the probability of a type 1 error is alpha
type 2 error
failed rejection of a false null hypothesis
the probability of a type 2 error is beta
power
probability of rejecting a false null hypothesis
power is the complement of the probability of type two error
power = 1-B
What does a statistical model represent in general?
Value of a dependent variable (y) as a function of one or more parameters plus an error term.
error term
variance of the dependent variable
Sample standard deviation
s = estimate of the population SD
leading to s/sqrtN instead of o/sqrtN because we don’t know o
sybar is the sample estimate of the standard error of the mean
When a mean is standardized using sybar instead of oybar the result follows what kind of distribution
t distribution instead of the standard normal distribution
t distribution
symmetric and bell-shaped
fatter tails or higher kurtosis which results from the added uncertainty due to estimating the standard error
The particular t-distribution we use depends on what?
the amount of sample info we have about the population value of the standard error. The particular t-distribution we use depends on the standard error.
The t distribution is equivalent to the standard normal distribution when …
df = infinity
power is greater when two things are present
- larger sample sizes
- larger effect sizes
error variance
extent that observations differ from the mean
sometimes referred to as an auxiliary parameter
intercept only model - error variance is equivalent to the variance of the dependent variable
sybar
sample estimate of the standard error of the mean
when does the result of a standardized mean follow a t-distribution?
when mean is standardized using sybar instead of oybar
