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32 Cards in this Set
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 Back
probability

# of outcomes classified as A/total # of possible outcomes


What are the requirements for a random sample?

Each individual has to have an equal chance of being selected; independent random sampling


inferential statistics

looking for noticeable difference


sampling distribution

all possible sample means


sampling error

natural discrepancy between a sample statistic and population parameter


expected value of M

µ


σM

standard error of Mhow much error between M and µ


sample size

as n increases σM decreases


how do you calculate standard error of M?

σ/√n or


hypothesis test

statistical method that uses sample data to evaluate a hypothesis about a population


type 1 error

reject null hypothesis that is actually true


type II error

failure to reject null that is really false


What effects the size of the mean difference?

numerator of the zscore; larger difference=increased likelihood of treatment effect


What effects the variability of he scores?

standard error, the number of scores in the sample


Increased variability

= deceased likelihood of treatment effect


Increased number of scores

= increased likelihood of treatment effect


What is the effect size?

measurement of the absolute magnitude of a treatment effect


statistical power

probability of correctly rejecting a false H0 or fail to reject H0


What is a tstatistic?

test hypothesis about an unknown population when σ is unknown


DF

number of scores in a sample that are independent


What are the factors that influence the t statistic?

sample size (increasing scores=increased likelihood if treatment effect, sample variance (large variance=decreased likelihood of treatment effect).


independent measures

two sets of data from two different groups, representative sample


Hartley FMax Test

tests for homogeneity of variance


repeated measures

single sample measured more than once, compare across conditions


matched subject design

1 subject matched to another on important characteristics: age, gender, IQ


What term is used to identify the mean of the distribution of sample means?

the expected value of M


Under what circumstance will the distribution of sample means be normal?

If the population is normal or if the sample size is greater than 30


The Central Limit Theorem

the standard error for a sample mean becomes smaller, approaching zero, and the sample size approaches infinity.


Describe a hypothesis test

an inferential technique that uses data from a sample to draw inferences about a population


Under what circumstances can a very small treatment effect still be signifcant?

if the sample size is very large.


What is the difference between a t statistic and a zscore?

The t statistic uses the sample variance in place of the population variance


What is measured by the estimated standard error?

the average distance between a sample mean and the population mean
