Research Methods And Statistics Part 2

Front 1

Magnitude

Back 1

An indication of the strength of the relationship between two variables.

Front 2

Scatter Plot

Back 2

A figure that graphically represents the relationship between to variables.

Front 3

Causality

Back 3

The assumption that a correlation indicates a causal relationship between the two variables.

Front 4

Directionality

Back 4

The inference made with respect to the direction of a causal relationship between two variables.

Front 5

Third Variable Problem

Back 5

The problem of a correlation between two variables being dependent on another (third) variable.

Front 6

Partial Correlation

Back 6

A correlation technique that involves measuring three variables and then statistically removing the effect of the third variable from the correlation of the remaining two variables.

Front 7

Restrictive Range

Back 7

A variable that is truncated and has limited variability.

Front 8

Person-who argument

Back 8

Arguing that a well-established statistical trend is invalid because we know a "person who" went against the trend.

Front 9

Pearson Product0Moment Correlation Coefficient (Pearson's r)

Back 9

The most commonly used correlation coefficient when both variables are measured on an interval or ratio scale.

Front 10

Coefficient of Determination (r2)

Back 10

A measure of the proportion of the variance in one variable that is accounted for by another variable, calculated by squaring the correlation coefficient.

Front 11

Spearman's Rank-Order Correlation Coefficient

Back 11

The correlation coefficient used when one (or more) of the variables is measured on an ordinal (ranking) scale.

Front 12

Point-Biserial Correlation Coefficient

Back 12

The correlation coefficient used when one of the variables is measured on a dichotomous nominal scale and the other is measured on an interval or ratio scale.

Front 13

Phi Coefficient

Back 13

The correlation coefficient used when both measured variables are dichotomous and nominal.

Front 14

Regression Analysis

Back 14

A procedure that allows us to predict an individual's score on one variable based on knowing one or more other variables.

Front 15

Regression Line

Back 15

The best-fitting straight line drawn through the center of a scatterplot that indicates the relationship between the variables.

Front 16

Probability

Back 16

The study of likelihood and uncertainty: the number of ways a particular outcome can occur , divided by the number of outcomes.

Front 17

Hypothesis Testing

Back 17

The process of determining whether a hypothesis is supported by the results of a research study.

Front 18

Multiplication Rule

Back 18

A probability rule stating that the probability of a series of outcomes occurring on successive trials is the product of their individual probabilities when the sequence of outcomes is independent.

Front 19

Addition Rule

Back 19

A probability rule stating that the probability of one outcome or another outcome occurring on a particular trial is the sum of their individual probabilities, when the outcomes are mutually exclusive.

Front 20

Null Hypothesis

Back 20

The hypothesis predicting that no difference exists between the groups being compared.

Front 21

Alternative Hypothesis (Alternative Hypothesis)

Back 21

The hypothesis that the researcher wants to support, predicting that a significant difference exists between the two groups being compared.

Front 22

One-tailed Hypothesis (Directional Hypothesis)

Back 22

An alternative hypothesis in which the researcher predicts the direction of the expected difference between the groups.

Front 23

Two-tailed Hypothesis (Non-directional Hypothesis)

Back 23

An alternative hypothesis in which the researcher predicts that the groups being compared differ but does not predict the direction of the difference.

Front 24

Type 1 Error

Back 24

An error in hypothesis testing in which the null hypothesis is rejected when It is true.

Front 25

Type II Error

Back 25

An error in the hypothesis testing in which the null hypothesis is accepted when it is false.

Front 26

Statistical significance

Back 26

An observed difference between two descriptive statistics (such as means) that is unlikely to have occurred by chance.

Front 27

Single-group Design

Back 27

A research study in which there is only one group of participants.

Front 28

Inferential Statistics

Back 28

Procedures for drawing conclusions about a population based on data collected from a sample.

Front 29

Non-Parametric Test

Back 29

A statistical test that does not involve the use of any population parameters, mean and standard deviation are not needed, and the underlying distribution does not have to be normal.

Front 30

Parametric Test

Back 30

A statistical test that involves making assumptions about estimates of population characteristics, or parameters.

Front 31

Z Test

Back 31

A parametric inferential statistical test of the null hypothesis for a single sample where the population variance is known.

Front 32

Sampling Distribution

Back 32

A distribution of sample means based on random samples of a fixed size from a population.

Front 33

Standard Error of the Mean

Back 33

The standard deviation of the sampling distribution.

Front 34

Central Limit Theorem

Back 34

A theorem that states that for any population with a mean and a standard deviation the distribution of sample means for sample size N will hava mean of , a standard deviation of and will approach a normal distribution as N approaches infinity.

Front 35

Critical Value

Back 35

The value of a test statistic that marks the edge of the region of rejection in a sampling distribution, where values equal to it or beyond it fall in the region of rejection.

Front 36

Region of Rejection

Back 36

The area of a sampling distribution that lies beyond the test statistic's critical value, when a score falls within this region, the null hypothesis is rejected.

Front 37

Statistical Power

Back 37

The probability of correctly rejecting a false null hypothesis.

Front 38

Confidence Interval

Back 38

An interval of a certain width that we feel confident will contain the mean.

Front 39

T Test

Back 39

A parametric inferential statistical test of the null hypothesis for a single sample where the population variance is not known.

Front 40

Student's t Distribution

Back 40

A set of distributions that, although symmetrical and bell shaped, are not normally distributed.

Front 41

Degrees of Freedom

Back 41

The number of scores in a sample that are free to vary.

n-1

Front 42

Estimated Standard Error of the Mean

Back 42

An estimate of the standard deviation of the sampling distribution.

Front 43

Chi Square (X2) Goodness-of-fit Test

Back 43

A non-parametric inferential procedure that determines how well an observed frequency distribution fits an expected distribution.

Front 44

Observed Frequency

Back 44

The frequency with which participants fall into a category.

Front 45

Expected Frequency

Back 45

The frequency expected in a category if the sample data represent the population.