Lumina
Applied Health Statistics · Level 0
EN PT
Optional orientation · before HEALTH.1

Before you begin: check the foundations

You do not need to know statistical tests or programming to begin this course. Use this optional review if you want to practise three foundations first: what one row represents, what is being compared, and what a result can and cannot support. If those ideas already feel familiar, continue directly to HEALTH.1.

what you'll be able to doDescribe a health-research question in five plain-language lines—population, unit, outcome, comparison, and dependence—before choosing any calculation.

What must be clear before any calculation

Read this route from left to right. First decide whom the question concerns and what is being compared. Then confirm what was measured and whether observations come from different people or repeated measurements of the same person. Only after those choices does an analysis method have a clear meaning.

research questionpopulation + comparisonmeasurementunit + outcome + scaledependenceseparate, paired, repeatedanalysis planeffect + interval

The trap: calculating before identifying what was measured

A spreadsheet contains blood-pressure values at discharge and 30 days later. If both rows belong to the same person, the measurements are linked; if they belong to different people, they are separate. A calculation performed before checking that relationship can answer the wrong question even when the software runs without error. Design and measurement determine what the numbers mean. The discussion of units follows the public explanation by Altman and Bland.

not an examChoose “review” whenever you are unsure. The result stays in your browser, does not block the course, and should never be interpreted as a clinical or professional credential.
how to use this orientationThe choices below only assemble a personal review list. They do not grade you, diagnose ability, or decide whether you may continue. Each item points to a short explanation you can revisit whenever the idea becomes useful in the course.

Choose what you want to review

For each item, choose “ready” if the sentence already makes sense or “review” if you want the short explanation below. There is no score or pass mark. The activity works without a server and sends no response anywhere.

01Population, sample, unit

I can distinguish who I want to understand, who was observed, and what one row represents.

02Outcome, exposure, comparison

I can name what changes, what may explain it, and the reference for the contrast.

03Variable scale

I can tell labels with no order (blood group), ordered categories (mild/moderate/severe), counts (number of visits), and measurements on a numerical scale (blood pressure) apart. Statisticians call these nominal, ordinal, discrete, and continuous variables.

04Dependence

I can tell measurements from different people from measurements linked to the same person. The link is called dependence; ignoring it makes repeated measurements look like extra independent information.

05Description

I can read counts, proportions, mean/SD, median/IQR, tables, and honest displays.

06Numeracy

I can work with percentages, ratios, subtraction, division, and elementary rearrangement.

07Uncertainty

I can distinguish a point estimate from a confidence interval.

08Execution

I can open a CSV and copy one prepared Python or R command from the correct folder.

Stored only in this browser on this device. You may reset it at any time; the result never blocks HEALTH.1.

a file has two visits per participant. What does one row represent?
A visit, not necessarily a participant. The participant identifier links rows; analyses that assume every row is independent would discard that dependence.

If you marked an item for review, use the matching activity below. You may also start HEALTH.1 now and return here when the idea appears in context.

Your optional review route

Follow the list generated above or browse the eight short activities. Work through only what helps, then return to the question and explain the idea in your own words.

01 · Population, sample, unit

Write three separate nouns: the people the question concerns, the records observed, and what one row represents. Then ask whether one row is a person or a visit. Continue with HEALTH.1.

02 · Outcome, exposure, comparison

Name the outcome, the exposure or intervention, and the reference comparison. Do not choose a test until the contrast and time horizon are explicit.

03 · Variable scale

Classify each field as a label, ordered category, count, measurement, date, or identifier. HEALTH.2 turns those labels into a data dictionary.

04 · Dependence

Two different participants are independent; two visits from one participant are repeated; a deliberately matched control pair is paired. The identifier—not the row count—reveals the structure.

05 · Description

For values 2, 3, 3, 4, 18, compare the mean with the median and identify the unusual value. For every percentage, write its numerator and denominator. HEALTH.3 expands this into the descriptive profile.

06 · Numeracy

If 6 of 24 records meet a rule, calculate 6 ÷ 24 = 0.25 = 25%. Then express the contrast as 6:18 and the percentage-point difference against a stated reference.

07 · Uncertainty

Read “effect 2.1; 95% CI 0.4 to 3.8” as one sample estimate plus a range produced by a declared interval method—not as a guarantee that every value is equally plausible. HEALTH.4 develops the interval contract.

08 · Execution

Programming is optional. If you choose technical practice, first open the AURORA-30 orientation; it introduces the fictional practice cohort, local files, and guided execution route separately from this course-start orientation.

Your turn: describe one study in five lines

One completed example: adults starting a blood-pressure program. One row represents one person. The outcome is systolic pressure at day 30, and the comparison is program minus usual care. Each person contributes one day-30 measurement. Notice that the comparison and dependence are stated before choosing a method.

Without software, write five lines for any health-research question: population, unit, outcome, comparison, and dependence. If one line is vague, use the matching review activity. You may begin HEALTH.1 before or after this exercise.

key takeaways