Inferential statistics Flashcards
Probability
Probability is used to predict the type of samples that are likely to be obtained from a population. Thus, probability establishes a connection between samples and populations
Sampling distribution of means
A frequency distribution showing all possible sample means that occur when samples of a particular size are drawn from a population
Central limit theorem
A statistical principle that defines the mean, standard deviation, and shape of a sampling distribution
Standard error of the mean
The standard deviation of the sampling distribution of means
Representative sample
A sample in which the individuals and scores accurately reflect the individuals and scores in the population
Sampling error
When random chance produces an unrepresentative sample from a population, with the result that the sample’s statistic is different from the population parameter it represents
Region of rejection
The part of a sampling distribution containing means that are so unlikely that we reject that they represent the underlying raw score population
Criterion
The probability that defines whether a sample is unlikely to represent the underlying raw score population
Critical value
The score that marks the inner edge of the region of rejection in a sampling distribution; values that fall beyond it lie in the region of rejection
Inferential statistics
Procedures for deciding whether sample data represent a particular relationship in the population
Parametric statistics
Inferential procedures that require certain assumptions about the raw score population represented by the sample; used when we compute the mean
Nonparametric statistics
Inferential procedures that do not require stringent assumptions about the raw score population represented by the sample; used with the median and mode
Experimental hypotheses
Two statements describing the predicted relationship that may or may not be demonstrated by a study
Two-tailed test
The type of inferential test used when we do not predict whether dependent scores will increase or decrease
One-tailed test
The type of inferential test used when we predict that dependent scores will only increase or will only decrease
Statistical hypothesis
Statements that describe the population parameters the sample statistics represent if the predicted relationship exists or does not exist
Alternative hypothesis
The hypothesis describing the population parameters the sample data represent if the predicted relationship does exist in nature
Null hypothesis
The hypothesis describing the
population parameters the sample data represent if the predicted relationship does not exist in nature
z-test
The parametric procedure used in a single-sample experiment when the standard deviation of the raw score population is known
Alpha (a)
The Greek letter that symbolizes the criterion probability
Significant
Describes results that are unlikely to result from sampling error when the predicted relationship does not exist; it indicates rejection of the null hypothesis
Nonsignificant
Describes results that are likely to result from sampling error when the predicted relationship does not exist; it indicates failure to reject the null hypothesis
Type 1 error
Rejecting the null hypothesis when it is true (that is, saying the independent variable works when it does not)
Type 2 error
Retaining the null hypothesis when it is false (that is, failing to identify that the independent variable does work as predicted)
Power
The probability that we will detect a relationship and correctly reject a false null hypothesis; the probability of avoiding a Type II error
Cohen’s d
d = Sample mean difference / Sample standard deviation
