Statistical Primer for Athletic Trainers: Understanding CIs and Effect Sizes

Effect Size

Magnitude of difference between 2 means, independent of sample size

Confidence Interval

Range likely to include the population parameter of interest

Clinical Meaningfulness

Relevance of results to athletic training practice

Statistical Significance

Reflects chance influence on study outcome

Null Hypothesis

States no difference between groups or across time

Standardized Effect Size

Magnitude of difference between 2 means on a unitless scale

Sample Data

Data collected to estimate population parameters

Margin of Error

Range of values likely to capture true treatment difference

Statistical Confidence

Level of confidence in the range of values

Precision

Width of confidence intervals affecting clinical utility

Variability of Data

Differences in responses among individuals in a study

Level of Confidence

Degree of certainty in the range of values

Sample Size

Number of subjects in a study, affects CI width

Variability

Differences in responses among study participants

Meaningful Change

Change in outcome considered clinically significant

Minimal Detectable Change

Threshold value for true change beyond measurement error

Clinical Decisions

Choices made based on clinical significance of study results

Reproducibility

Ability to obtain consistent results on repeated measurements

Magnitude of Effects

Size of differences between groups or conditions

Meta-analysis

Statistical analysis combining results from multiple studies

Power Analysis

Determines sample size based on effect size

Standardized Effect Sizes

Computed as difference divided by standard deviation

Cohen Categories

Classification of effect sizes as small, medium, or large

Standard Normal Distribution

Describes distribution in terms of z-scores

Confidence Interval (CI)

Range with estimated likelihood of including population parameter

Pooled Standard Deviation

Combined standard deviation of two groups

Rhea Criteria

Interpretation of effect size in research

Interpretation Conventions

Guidelines for assessing effect sizes in different fields

Standardizer

Denominator used in computing effect sizes

Meaningful Difference

Significance of difference between groups

Effect Size Calculation

Formula using means and standard deviation

Clinical Research Appraisal

Evaluation of research findings for practical application

Overlap Interpretation

Using distribution overlap to assess effect size

Effect Size Interpretation

Understanding the practical implications of effect sizes

Sample Distribution

Distribution of scores in a sample

Effect Size Template

Guideline for interpreting effect sizes in research

Effect Size Magnitude

Degree of difference between groups

Effect Size Classification

Categorization of effect sizes based on magnitude

Effect Size Reporting

Inclusion of effect sizes in research findings

Effect Size Comparison

Assessing differences between groups using effect sizes

Effect Size Importance

Significance of effect sizes in research interpretation