HOME
Course Chapters
Mathematics Review
Basic Concepts
Advanced Concepts
Section Tests
Pretest
Posttest
Useful Materials
Glossary
Links
Texas Instruments Calculators
Casio Calculators
Sharp Calculators
Hewlett Packard Calculators
Calculators
Units Conversion Lookup
Nomenclature
Redox
Kinetics
Thermo
Nuclear
Linear Least Squares Regression
Newton's Method Equation Solver
Gas Laws
Credits
Contact Webmaster

Simple Statistics
A student analyzing a sample for bromine (Br) makes four trials with the following results: 36.0, 36.3, 35.8, and 36.3. The theoretical value is 36.2
Calculate:
 the arithmetic mean
 the percent error for each trial
 the deviation and percent deviation for each trial
 the standard deviation
Arithmetic mean:
(36.0 + 36.3 + 35.8 + 36.3) / 4 = 36.1
Percent error, deviation and percent deviation for each trial
Observed value 
Error 
Percent error 
Deviation 
Percent deviation 
36.0 
0.2 
0.55% 
0.1 
0.28% 
36.3 
0.1 
0.28% 
0.2 
0.55% 
35.8 
0.4 
1.1% 
0.3 
0.83% 
36.3 
0.1 
0.28% 
0.2 
0.55% 
Standard deviation
Trial 
1 
2 
3 
4 
Percentage of Br 
36.0 
36.3 
35.8 
36.3 
d 
0.1 
0.2 
0.3 
0.2 
d^{2} 
0.01 
0.04 
0.09 
0.04 
Adding up all of the d^{2}= 0.18
Dividing 0.18 by 3 (or 41) = 0.06
Taking the square root of 0.06= 0.245
Back to Statistics Main Page
