Center by personMake the data structure visible.
Test slope differencesRecord checks and uncertainty.
Probe observed supportConnect output to interpretation.

WHAT IS INSIDE

A reproducible path through the workflow.

01

Audit moderator consistency

Confirm one moderator and program value per student and unique person-time records.

02

Fit nested growth models

Compare main-effects and interaction models on the same estimation sample.

03

Calculate simple slopes

Estimate conditional time slopes with t-based confidence intervals.

04

Visualize the interaction

Show confidence-banded trajectories and a pointwise slope-interval grid over observed values.

SCOPE AND BOUNDARIES

Match the workflow
to the question.

Before adapting the example:

  • Define the unit, repeated-measure schedule, and time origin.
  • Run the complete synthetic example.
  • Use only a de-identified working copy of real data.
  • Review model or transformation assumptions with the committee.

The slope grid uses pointwise intervals; it is not an exact or simultaneous Johnson-Neyman region. An interaction does not establish causation.

OUTPUT-ONLY PUBLIC PREVIEW

Explore the complete worked example.

Open full screen ↗
Probing Interactions in Growth Models · Dissertation Stats Helper

The preview shows results, figures, and guidance. The paid version includes all editable source and reusable code. Source code and session information are omitted.

YOUR DIGITAL DOWNLOAD

Run the example.
Make it your own.

  • Complete editable R Markdown source
  • Synthetic data and reproducible generator
  • Worked HTML report and reusable exports
  • Dynamic reporting and diagnostic guidance
  • Setup, generation, version, and license documentation

VERSION 1.0.0

Complete workflow.
$59 one time.

Pay securely and receive the version 1.0.0 ZIP with the editable analysis, synthetic data, documentation, and rendered report.

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