Descriptive Statistics Table​, Example & Meaning

Biostatistics provides essential links for researchers and scientists to analyze and interpret biological and health-related data, and biostatistics stands at the center of biology and statistical methods. Descriptive statistics form the foundation of biostatistical analysis, offering researchers ways to organize, summarize, and present biological data before applying more complex analytical techniques.

Descriptive statistics in biostatistics allow researchers to describe their biological data using graphical representations and numerical summaries. These techniques transform raw biological measurements into insightful information that might affect scientific and clinical decisions. In biostatistics, descriptive statistics help researchers make sense of complex biological or medical data by providing a quick overview of the essential features of a dataset.

Key Functions of Descriptive Statistics

Summarize Data

Turn raw data into simple summaries.

Example: Average blood pressure in a study group.

Describe the Distribution

Show how data points are spread or clustered.

Example: Range of white blood cell counts in patients.

Detect Patterns

Highlight trends or outliers in health or biological datasets.

Common Types of Descriptive Statistics

TypeExamplesWhat It Tells You
Measures of Central TendencyMean, Median, ModeWhere the center of your data lies.
Measures of DispersionRange, Variance, Standard DeviationHow spread out the data is.
Measures of ShapeSkewness, KurtosisThe shape or symmetry of the data distribution.
Data VisualizationHistograms, Box Plots, Bar ChartsVisual summaries for quick understanding.

Categories of Descriptive Statistics

1

Measures of Central Tendency

These tell you where the "center" of the data lies.

  • Mean (Average): The sum of all values divided by the number of values (Arithmetic, Geometric and Harmonic).
  • Percentile: Value with the rank (P/100)(1+n).
  • Median: The middle value when the data is ordered. 50th of percentile.
  • Mode: The value that appears most frequently.
2

Measures of Dispersion (Spread)

These describe how much variation exists in the data.

  • Range: Difference between the highest and lowest values.
  • Variance: A measure of how far each number in the set is from the mean.
  • Standard Deviation: The square root of variance; a key measure of spread.
3

Measures of Shape (Distribution)

These help you understand the overall structure of the data.

  • Skewness: Indicates Symmetry of dataset. If data is skewed left or right. Negative means skewed to the left (tail towards left), 0 is symmetric.
  • Kurtosis: Indicates peakedness of dataset. Negative means platykurtic, 0 is normal, positive is leptokurtic, that is whether data are heavy-tailed or light-tailed compared to a normal distribution.

Data Visualization in Descriptive Statistics

Histograms: Show frequency distribution of data

Histograms visualize the distribution of continuous biological variables, such as showing how body mass index (BMI) is distributed across a population or how response times to medication vary among patients.

Box Plots: Display median, quartiles, and outliers

Box plots are excellent for comparing distributions of biological measurements across different groups, such as comparing lung capacity across different treatment groups in an asthma study.

Scatter Plots: Summarize categorical data

Scatter plots help visualize relationships between two biological variables, such as the correlation between cholesterol levels and blood pressure or between drug dosage and therapeutic response.

Applications of Descriptive Statistics in Biomedical Research

Epidemiological Studies

Descriptive statistics characterize disease prevalence, incidence rates, and demographic patterns of health conditions across populations. For instance, calculating age-adjusted rates allows meaningful comparisons of disease occurrence across populations with different age structures.

Clinical Trials

In pharmaceutical descriptive statistics research help to summarize baseline traits of study subjects, outcomes of treatment, and adverse effects. They form the basis for subsequent inferential analyses that determine treatment efficacy and safety.

Laboratory Research

In basic science and laboratory settings, it helps characterize the distribution of experimental measurements, identify outliers in experimental data, and summarize results from repeated experiments to assess reproducibility.

Genomics and Bioinformatics

Descriptive methods summarize the frequency of genetic variants, gene expression levels, and other molecular characteristics across different populations or disease states.

The Relationship Between Descriptive and Inferential Biostatistics

Descriptive statistics in biomedical research often serve as a precursor to inferential methods. These methods guide researchers in selecting appropriate statistical tests by revealing the underlying distribution of the data. For example, recognizing that a dataset is skewed may prompt researchers to use non-parametric tests rather than those that assume normality.

AspectDescriptive StatisticsInferential Statistics
Role in BiostatisticsProvides a summary of collected biological or clinical dataMakes predictions or generalizations about a larger population based on sample data
PurposeTo describe key features of the datasetTo test hypotheses and draw conclusions beyond the immediate data
Key MeasuresMean, Median, Standard Deviation, Range, ProportionConfidence Intervals, P-values, t-tests, ANOVA, Regression
ApplicationSummarizing patient demographics, lab results, or baseline characteristicsComparing treatment effects, evaluating drug efficacy, assessing associations
Nature of AnalysisQuantitative summary — no conclusions beyond the data itselfProbabilistic inference — allows for generalization with a degree of confidence
Example in BiostatisticsCalculating average blood pressure in a sample groupTesting whether a new treatment significantly reduces blood pressure
Support in BioStat PrimeYes — through data summary tools and visual outputsYes — via built-in statistical tests and interpretation tools