Methods Chapter 10

Front 1

Data

Back 1

Numerical or categorical facts about specific people or things, espeically when such people or things are the objets of systematic investigation.

Front 2

Descriptive Statistics

Back 2

Statistics used to summarize or describe a set of observations

Front 3

Central tendency

Back 3

A statistical term for the average or most representative score in a set of observations.

Front 4

Dispersion (Variability)

Back 4

A statistical ter for the degree to which the typical score in a set of scores deviates from the mean or most representative score. As a measure of **** incrase, the mean becomes progressively less representative of the entire set of scores. The range and standard deviation are common measures of dispersion.

Front 5

Range

Back 5

A statistical term for the difference between the highest and the lowest score in a set of scores. It is the measure of dispersion.

Front 6

Standard Deviation

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A statistical term for the average amount that each of the sores in a sample differs from the sample mean. This is a very commonly used as a measure of dispersion.

Front 7

Rectangular Distribution

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A distribution of scores in which all of the scores occur with equal frequency or likelihood (the distribution of the probabilities of drawing cards of different values from a fair deck)

Front 8

Bimodal Distribution

Back 8

A distribution of scores in which two distinct ranges of scores are more common than any other scores.

Front 9

Normal Distribution

Back 9

A symmetrical, bell shapes distributed of scores in which one distinct score is more common than any other score. Most continuous physical and psychological measures (Height, SAT scores)

Front 10

Probability

Back 10

The number of specific outcomes that qualify as an event divided by athe total number of all possible outcomes (the probability of drawing an ace from a fair deck of cards is 4/52 or 1/13). Can never be lower than 0 or higher than 1.0

Front 11

Null hypothesis

Back 11

The statistical assumption that there is no relation between the indepent and dependent variables of interest in an investigation (the assumption that the researchers hypothesis is false)

Front 12

Alternative hypothesis

Back 12

The statistical assumption that there is a relation between the independent and dependent variables of interest in an investigation. (the assumption that the researchers prediction is true)

Front 13

Statistical significance

Back 13

The likelihood that an observed effect would occur by chance alone. This number is typically expressed with a p value to indicate the number of times out of 100 that the observed effect would occur by chance.

Front 14

Type 1 error

Back 14

Rejecting the null hypothesis when the null hypothesis is actually incorrect. That is, failing to conclue that a researcher's hypothesis is true when it is false

Front 15

Type II error

Back 15

Failing to reject the null hypothesis when the null hypothesis is actually incorrect. That is, failing to conclude that a researcher's hypothesis is true when it is in fact true.

Front 16

Alpha Level

Back 16

The probability value that serves as the standard for rejecting the null hypothesis in a statistical test. It is most commonly set at .05, meaning that researchers typically conclude that their findings are "real" only if findings as extreme as or more extreme than theirs would have occurred fewer than 5 times in 100 based on chance.

Front 17

Effect Size

Back 17

An indicator of the strength of the relation between two or more variables. Two common indicators are r and d.

Front 18

Restriction of Range

Back 18

The methodological problem of a lack of variability in participants' response to a survey question or dependent measure. This includes both floor effects and ceiling effects.

Front 19

Coefficient of determination

Back 19

The perfentage of variance in one variable that is accounted for by a person's score on another variable.

Front 20

Binomial effect-size display

Back 20

A simple, intuitive way to ullustrate the strength of the relation between two dichotomous variables. IT involved categorizing participants in terms of their scores on each of the two dichotomous variables and entering the frequencies of these categorizations in a contingency table whose rows and columns sum to 100.

Front 21

Meta-analysis

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A set of statistical techniques for summarizing findings from a large set of studies to (1) determine the total amount of existing support for an effect, (2) assess the consistency or repeatability of the effect, and (3) identify determinants of the strength or magnitude of the effect across different studies.