chapter 11: one sample confidence interval Flashcards
4 criticisms of Ho testing
- it doesnt tell us if results are important or useful
- Ho tells us p(D⎮Ho) but we want to know p(Ho⎮D)
- it is a trivial exercise (john tukey) you can always find a difference to some decimal place if you have a large n
- 𝛂= .05 is arbitrary. a continuum of uncertainty becomes a reject-do-not-reject decision
- “surely god loves the .06 nearly as much as he loves the .05” (rosnow and rosenthal)
what is a confidence interval?
a confidence interval is a segment or interval on a number line such that 𝛍 has a high probability of lying on the segment
*can be either 1 or 2 sided
(a type of interval estimate of a population parameter)
what is confidence coefficient?
confidence coefficient is the probability that the interval contains 𝛍
when is a one sided confidence interval constructed?
a one sided confidence interval is constructed when the researcher has made a directional prediction about the population mean; otherwise the researcher constructs a two sided interval
purpose of calculating a confidence interval?
to provide a range of values that, with a certain measure of confidence, contains the population parameter of interest.
the 3 assumptions
- random sampling
- population is normally distributed
- population SD is unknown
interval estimation vs. hypothesis testing
confidence interval provides more information that the null hypothesis test
it can also be used to test any null hypothesis for 𝛍 simply by looking at the interval
effect magnitude statistics
a measure of the practical significance of results
- measures of effect size
- measures of strength of association
what is hedges g
hedges g is an estimator for cohens effect size parameter, d
- the g statistic is interpreted the same as cohens d
- g can be computed from a one sample t statistic
