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Lady Tasting Coffee

A Case Study in Experimental Design


Author(s)

Jacinth Maynard
Division of Physical and Computational Sciences
University of Pittsburgh at Bradford
jmaynard@lhup.edu
Mary Puterbaugh Mulcahy
Division of Biological and Health Sciences
University of Pittsburgh at Bradford
mnp1@exchange.upb.pitt.edu
Daniel Kermick
Division of Biological and Health Sciences
University at Pittsburgh at Bradford

Abstract

In the 1920s, biologist and statistician Ronald Fisher met a woman who claimed she could taste whether a cup of tea was prepared by adding milk before or after the tea. Fisher’s essay about the tea party may be one of the first cases published to teach the process of science. The present case is a modernized version of Fisher’s story and concerns the ability of a woman to distinguish between cups of coffee with milk added first or second. The case is enhanced by a demonstration in which students distinguish between 2% and skim milk, brands of bottled water, or brands of soda.


Objectives

  • Understand concepts of experimental design, especially randomization, replication, and the probability of obtaining extreme results by chance.
  • Be able to state the null hypothesis for a simple experiment.
  • Design a simple experiment including select samples and apply treatments, establish the level of significance, and make appropriate conclusions based on significance levels.

Keywords

Experimental design; randomization; probability; statistics; Ronald Fisher

Topical Areas

History of science, Scientific method

Educational Level

High school, Undergraduate lower division

Format

PDF, PowerPoint

Type / Methods

Demonstration, Interrupted

Language

English

Subject Headings

Biology (General)  |   Statistics  |  


Date Posted

08/19/09

Teaching Notes

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Supplemental Materials

This case includes a supplemental PowerPoint presentation that instructors can use to provide students with background information on Ronald Fisher and his essay, "Mathematics of a Lady Tasting Tea," on which the case is based.


  lady_tasting_tea_suppl.ppt

Answer Key

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