PSYCH501 Module 1

clearly defined collection of people, animals, plants, or objects; usually a specific group of people

the measurement of the attribute of interest

• measurement with the following properties:
• 0 represents comple absence
• ratio of any two scores correctly describes ratio of attribute quantites
• difference between two scores correctly describes difference in attribute quantities

• measurement with the following properties:
• 0 does not represent complete absence
• ratio of any two scores does not correctly describe ratio of attribute quantites
• difference between two scores correctly describes difference in attribute quantities

ratio or interval scale measurement

single unknown numeric value that describes the measurements that could have been assigned to all N people in a specific study population

an unknown value; the average of all N scores that could have been assigned to all N people in a study population

a set of a study population of size n, selected in such a way that any set of size n has an equal chance of being selected

an estimate of µ; the average of all scores from the sample

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• value that numerically describes the accuracy of a parameter estimate

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• describes the variability of the scores in the sample

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• estimate of ơ; describes the variability of the scores in a sample

range of values that is believed to contain an unknown population parameter value with some specified degree of confidence

H0: µ = h; states that the mean is equal to some specified value

₁a general hypothesis testing procedure in which one of the following decisions will be made: 1) accept H_1, 2) accept H₂, 3) fail to reject H₀

a value obtained from a t-test, used to determine whether or not to reject the null hypothesis

a test of the null hypothesis applied to a single population mean

a number determined by the test statistic; small p-values correspond to high test statistics and the researcher may reject the null hypothesis if p is less than α (usually .05)

an alternative to hypothesis testing where results are declared "significant" if the p-value is less than some set value, usually .05

graph that visually displays a set of quantitative scores; displays the number of scores falling into specified ranges of scores

• a curve in which:
• half of the scores are above the mean and half are below (the mean, median, and mode are identical)
• 68% of scores are within 1 standard deviation above or below the mean
• 95% of scores are within 2 standard deviations above or below the mean
• 99.7% of scores are within 3 standard deviations above or below the mean

the set of all possible sample means obtained from all possible samples in the study population

states that if the sample size is sufficiently larg, the distribution of the sample means will be closely approximated by a normal distribution

an estimate which overestimates the population parameter with about the same tendency as it underestimates the population parameter

a number on a 0 to 1 scale that describes the likelihood of an event

the proportion of all possible events that are of the type in question

the probability of rejecting the null hypothesis

rejecting the null hypothesis when, in reality, µ = h

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• a range of plausible scores for one randomly selected person

a value obtained from experts, preliminary studies, or previoiusly published research

a population of interest to the researcher from which the study population is taken

nonrandom samlle obtained for ease or availability

requires the sample to be a random sample from the study population or some hypothetical population

requires that the responses from each participant in the study be independent of each other

requires that the scores in the study population have approximately a normal distribution

numerically describes the skewness of a set of scores; zero if scores are symmetrical, positive if scores are skewed right, negative if scores are skewed left

describes to degree to which a distribution is more less peaked than the normal distribution; equal to 3 in normal curve (coefficient - 3 = excess kurtosis), excess kurtosis > 0 is highly peaked with long tails, excess kurtosis < 0 is lower peaked with short tails

scores are all manipulated mathematically to reduce skewness and kurtosis