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Description

As explained in Effective Data Analysis

A descriptive method summarizes observed characteristics of data without testing an intervention or manipulating a condition.

Description summarizes observed data or a phenomenon without manipulating a test variable or condition. It supports understanding new data sources, developing metrics, sizing opportunities, and informing decisions. section 3.2.1

Descriptive analysis can use quantitative or qualitative data and commonly reports:

  • Central tendency, including mean, median, and mode. section 3.2.1
  • Distribution measures, such as standard deviation for continuous data. section 3.2.1
  • Counts and proportions for categorical data. section 3.2.1
  • Trends over time, group differences, or other summaries selected after exploring the dataset. section 3.2.1

Descriptive statistics may stand alone in reports and dashboards or provide context for inferential analysis. Choose measures carefully: distribution shape affects interpretation, and omitting a statistic can change what stakeholders conclude. Descriptive results describe observed patterns but do not test an intervention. section 3.2.1 section 3.2

Rat-sighting trends

A daily dataset of rat sightings can be plotted over time, grouped by month, and summarized with monthly totals, means, and medians. Comparing the mean and median helps communicate how the reported sightings vary across months.

How Effective Data Analysis covers it

How deep it goes
Explains summaries, selection considerations, and time aggregation, but stops short of testing causal effects or interventions.
Examples
Uses daily and monthly New York City rat-sighting plots, totals, means, medians, counts, proportions, and distribution measures.
What it assumes
Assumes a defined question and collected data while teaching measure selection, dataset exploration, and interpretation from basic summaries.
What you can do after
Apply it via pandas and Matplotlib to summarize datasets, visualize trends, compare groups, and communicate decision-relevant patterns.
How it connects
Connects descriptive statistics with observational research, inferential statistics, correlations, experiments, metrics, and dashboards.

Related concepts

This explainer was generated by Manning's knowledge graph from the text of Effective Data Analysis. The section links point to the parts of the book it draws on.