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Ch.4 + 5 - Statistics, Quality Assurance and Calibration MethodsWorksheetSee all chapters
All Chapters
Ch.1 - Chemical Measurements
Ch.2 - Tools of the Trade
Ch.3 - Experimental Error
Ch.4 + 5 - Statistics, Quality Assurance and Calibration Methods
Ch.6 - Chemical Equilibrium
Ch.7 - Activity and the Systematic Treatment of Equilibrium
Ch.8 - Monoprotic Acid-Base Equilibria
Ch.9 - Polyprotic Acid-Base Equilibria
Ch.10 - Acid-Base Titrations
Ch.11 - EDTA Titrations
Ch.12 - Advanced Topics in Equilibrium
Ch.13 - Fundamentals of Electrochemistry
Ch.14 - Electrodes and Potentiometry
Ch.15 - Redox Titrations
Ch.16 - Electroanalytical Techniques
Ch.17 - Fundamentals of Spectrophotometry
BONUS: Chemical Kinetics
Mean Evaluation
The Gaussian Distribution
Confidence Intervals
Hypothesis Testing (t-Test)
Analysis of Variance (f-Test)
Detection of Gross Errors

A confidence interval is a specific interval estimate of a parameter determined by using data obtained from a sample. 

Confidence Intervals

Concept #1: The percentage in a confidence interval represents the level of certainty that we have for the mean lying within a given range. 


Example #1: Construct a 95% confidence interval for an experiment that found the mean temperature for a given city in July as 103.5 oC with a standard deviation of 1.8 from 10 measurements.  

Example #2: The barium content of a metal ore was analyzed several times by a percent composition process.

0.010             0.011             0.004             0.011

Calculate the mean, median and mode. 

Example #3: From EXAMPLE 1, calculate the standard deviation. 

Practice: From the examples given above, find the 90% confidence interval.