What is an independent variable?

a constant variable that can be manipulated by the researcher

What is a dependent variable?

a variable that is dependent on results which are measured by the researcher

What is a covariate?

a phenomenon that affects the dependent that is not of interest to the researcher, but the researcher is unable to control

What is a extranenous or confounding variable?

a phenomenon that are not of interest but may have an effect on the value of the dependent variable

What is intra and inter rater reliability

how consistent one person is at measuring something vs how consistently a group of individuals can consistently measure something

What is ANOVA (analysis of variance) used for?

statistical procedure to estimate reliability

What is randomized, repeated measures, and factorial research designs

randomized: everything is randomized; repeated: all subjects measured against the same variables; factorial has multiple independent variables and measures all subjects against all variations

What is used to calculate the association between two variables?

correlation coefficient

What statiscal test is used to predict?

regression analysis

What statiscal test is used to see if a Tx has an effect?

chi square, ANOVA, or T-test

Study types in a hierarchial manner?

RCT, cohort study, case-control study, case series, descriptive study

What is a meta anaylsis?

a variety of systematic reviews (a thorough review and summary of the research)

How to remember specificity and sensitivity

Sp In Sn out

Reliability

Stability, repeatability, and dependability of a test or measure

Intra-rater Reliability

Consistency of a measure made by the same person

Inter-rater Reliability

Consistency of a measure made by 2 or more people

Validity

Appropriateness, truthfulness, authenticity, effectiveness of a test or measure

Face Validity:

The appearance of a test or measure

Construct Validity

The extent to which a tool measures what it claims to measure

Content Validity

Does the test truly sample the behavior that I wish to study

Concurrent Validity:

The relationship between test scores of what is being measured (test #1) and what it is being compared to (test #2)

Predictive Validity

can a future prediction be based on a measure made today

Internal Validity:

refers to the relationship between the dependent variable and the independent variable. A study will have high internal validity when all the factors that might cause a change in the dependent variable are controlled

External Validity:

the generalization from the sample studied to the population

Independent Variable

the “intervention” being studied

Dependent Variable

the outcome measure used to study the independent variable

Power

the probability of reaching a correct decision. Most statistical tests should have a power of at least 0.70

Null hypothesis

the prediction that there will be no statistically significant difference between data sets

Type 1 Error:

Stating there is a difference between two treatments when there is not; rejecting the null hypothesis when we should accept it (backing a loser) - The greater the power of a test, the less likely we are of having a Type 1 Error

Type 2 Error:

Reject the null hypothesis and stating there is no difference when in fact there is (missing a winner). - Usually occurs due to a small sample size

Sensitivity:

SnNout: high sensitivity (sn), when negative (n), rules out (out) the pathology

Specificity

SpPin: high specificity (sp), when positive (p), rules in (in) the pathology

Meta-analysis:

a systematic review that uses statistical modeling to summarize the quantitative results from similar studies. Studies must have a high degree of homogeneity in design, methods and data reporting. These are limited representations of the literature that are primarily designed to show either the positive or negative direction of research on a given topic

When is Kappa coefficient (very prevalent in the literature) used

Nominal: Name only data

When is Spearman Rho used?

Ordinal: a scale that implies a rank order (intervals between scores are not even

When is Pearson correlation coefficient used?

Interval/Ratio/Metric: a rank order with consistent intervals between scores

What is a regression analysis used for?

prediction

Does a treatment have an effect: nominal data what statistical test is used:

Chi squared - yes/no question

Does a treatment have an effect: ratio data what statistical test is used?

ANOVA or t-test (do 2 or more groups differ on the outcome variable?)