Brown: Chapter 6

Question 1

Several research designs are linked to inferential relationship statistics, such as:

Answer 1

Nonexperimental, cross-sectional relationship studies
Predictive studies
Case-control, cross-sectional predictive studies
Cohort studies in which data is prospectively or retrospectively collected over time

Question 2

What is a Pearson product-moment correlation?

Answer 2

Describes the strength of the relationship between 2 continuous variables
Used in nonexperimental and cross-sectional relationship studies

Question 3

What is a Spearman correlation?

Answer 3

Describes the strength of the relationship between 2 variables when at least one variable is rank-ordered
Used in nonexperimental and cross-sectional relationship studies

Question 4

What is a linear regression?

Answer 4

Identifies predictors of a continuous outcome measure
Used in predictive studies
Several variables (predictors) are entered into a regression equation to determine how well they predict an outcome of interest (criterion); the outcome variable is continuous

Question 5

What is an odds ratio?

Answer 5

Identifies predictors of a dichotomous outcome measure; best when the frequency of the outcome occurring is rare
Used in case-control and cross-sectional predictive studies
Best applied to cross-sectional studies in which the event or outcome has already occurred

Question 6

What is a risk ratio?

Answer 6

Identifies predictors of a dichotomous outcome measure
Used in cohort studies in which data is either prospectively or retrospectively collected over time
Used to determine whether an event or outcome occurs

Question 7

What is a hazards ratio?

Answer 7

Identifies predictors of a dichotomous outcome measure; often includes survival curve estimates
Used in cohort studies in which data is either prospectively or retrospectively collected over time
Provide information about the rate of change over time

Question 8

What does this symbol mean: AR

Answer 8

absolute risk

Question 9

What does this symbol mean: β

Answer 9

beta weight

Question 10

What does this symbol mean: CI

Answer 10

confidence interval

Question 11

What does this symbol mean: HR

Answer 11

hazards ratio

Question 12

What does this symbol mean: N, n

Answer 12

number of participants in a study

Question 13

What does this symbol mean: OR

Answer 13

odds ratio

Question 14

What does this symbol mean: p

Answer 14

probability value; the likelihood of making a type I error

Question 15

What does this symbol mean: r value

Answer 15

correlation coefficient

Question 16

What does this symbol mean: R2

Answer 16

variance; the amount of variance accounted for in a correlational study

Question 17

What does this symbol mean: R2 change

Answer 17

the amount of unique variance when a new variable or group of variables is added to a regression equation

Question 18

What does this symbol mean: RR

Answer 18

risk ratio or relative risk

Question 19

What is a correlation?

Answer 19

A correlation is a type of inferential statistic
that determines how much two or more
variables fluctuate together:
- Expressed in terms of strength, direction, and
significance
- Also represent effect sizes: the r value

Question 20

What is explained variance?

Answer 20

the proportion of one data set that accounts for the spread of numbers in a second data set

Question 21

What is a scatterplot?

Answer 21

a graph of plotted points that shows the relationship between two sets of data

Question 22

What does this scatterplot show?

Answer 22

positive relationship

Question 23

What does this scatterplot show?

Answer 23

no relationship

Question 24

What does this scatterplot show?

Answer 24

negative relationship

Question 25

What does this scatterplot show?

Answer 25

positive relationship

Question 26

What does this scatterplot show?

Answer 26

negative relationship

Question 27

What is a correlational matrix?

Answer 27

In a correlation matrix, all variables listed in the vertical left column are also listed across the top horizontal column to capture all relationships that exist between any two variables.

Question 28

Studies to predict outcomes use...

Answer 28

regression equations that calculate the degree to which two or more variables predict a specific outcome

Question 29

How are linear regression outcomes reported?

Answer 29

with β weights, R2, and R2 change statistics.

Question 30

What is β weight?

Answer 30

the standardized regression coefficient

Question 31

What is R2?

Answer 31

Coefficient of determination) The amount of variance accounted for by a single predictor or a group of predictors

Question 32

Linear regression allows for...

Answer 32

the removal of shared variance among predictors to determine which predictors contribute the most variance

Question 33

When does multicollinearity occur?

Answer 33

when two or more predictor variables are highly intercorrelated and means that each predictor provides only a small amount of unique variance

Question 34

The challenge of linear regression lies in choosing...

Answer 34

predictors: the amount of total variance accounted for shows how effective the researcher was in the selection of predictors.

Question 35

What does this picture show?

Answer 35

Multicollinearity, shared variance, and unique variance

Question 36

What is logistic regression?

Answer 36

a statistical method for analyzing a dataset in which the outcome is measured with a dichotomous variable (only two possible outcomes)

Question 37

With odds ratio, logistic regression is used to...

Answer 37

determine the association between a predictor or a set of predictors and a dichotomous outcome that has already occurred

Question 38

Confidence intervals are frequently reported with...

Answer 38

odds ratios

Question 39

What are risk ratios (relative risk)?

Answer 39

Used to compare one group that has been exposed to a condition and one group that has not A risk ratio then tells you if your absolute risk is raised or lowered based on a predictor or factor.

Question 40

When are risk ratios used?

Answer 40

Risk ratios are appropriate for cohort studies in which the participants are followed over time, after which they are divided into two groups based on a specific outcome. Risk ratios also can be used in retrospective analyses in which the researcher uses existing data to look back on participants to determine if they progressed or declined over time.

Question 41

What is a hazards ratio?

Answer 41

Hazards ratios report the likelihood of an event happening at a specific time point; however, most hazards ratios report multiple time points within a single study. Hazards ratio often includes the presentation of data over time in the form of Kaplan Meier curves that illustrate the duration of time for two (or more) groups to reach an outcome.

Question 42

What is this graph?

Answer 42

Kaplan-Meier curves comparing survival according to level of physical activity