ANALYZING EXPERIMENTAL DATA

for Engineering and Built Environment

Ir. Dr Naser Ghani anaser@usm.my www.hbp.usm.my/naser

2

Experiment

observation surveys

Four ways to collect data

Computer simulation

DATA

DATA ANALYSIS

Analysis should be driven by a sense of curiosity about the data. Relate it directly to the objectives. Some objectives may need to be dropped, and new objectives could be formed.

DATA ANALYSIS

Parametric Examination and description of relationship between different parameters/variables – e.g. strength/density, quantity/cost etc

Regression Estimating relationship among variables i.e. R2, Forecasting, prediction – i.e. regression line or formula.

Statistical

DATA TABLES AND GRAPHS

Layout of data table is based on the variables for the experiment/study. First column – independent variable/s Remaining columns – observed values

DATA TABLES

Gdbugdbak content (%)

Concrete Compression Strength (KPa)

Mix 1 Mix 2 Mix 3 Average 5 10 15 20 25 30

The Effect of Gdbukgdbak on Concrete Compression Strength

GRAPHS, CHARTS and GRAPHICS

GRAPHS, CHARTS and GRAPHICS

Easier to see trends and patterns Bring out the significance of data in visual format

•Qualitative caption •Quantitative data in charts and graphs •Graphical forms •Summary in Mathematical equation

GRAPHS, CHARTS and GRAPHICS

Independent Variable

Dependent Variable

Type of Graph

Scale with Intervals Eg. Strength, Height, Pressure, Weight, Volume, Intensity etc

Quantitative

Line

Qualitative

Frequency distribution

Discrete categories Eg. Day of week, gender, color, brand, location

Quantitative

Bar graph

Qualitative

Frequency distribution

DATA TABLES AND GRAPHS

GRAPHS, CHARTS and GRAPHICS

ANALATYCAL PRESENTATION

MATHEMATICAL RELATIONSHIP

SUMMARY OF DATA

CONCLUSION FROM ANALYSIS

• What was the purpose of the experiment? • What were the major findings? • Did this answer your questions? • How do your findings compare with other people's

experiments or with the information in your textbook? • What explanation can you think of for the findings? • How could this experiment be improved or extended?

References

M.A. JORDAN, N.POWELL, C.V. PHILLIPS and C.K.CHIN (1997). EXPERIMENTAL DATA ANALYSIS: A GUIDE TO THE SELECTION OF SIMPLE STATISTICAL TESTS Minerals Engineering, Vol. 10, No. 3, pp. 275-286, 199 …… (2000). Students and research: Practical strategies for science classrooms and competitions. Cothron, J. H., Giese, R. N., & Rezba, R. J. (3rd Ed.). (2000). Dubuque, IA: Kendall/Hunt Publishing Company. C.A. Peters (2011). Statistics for Analysis of Experimental Data. Published as a chapter in the Environmental Engineering Processes Laboratory Manual S. E. Powers, Ed. AEESP, Champaign, IL 2001 Srinagesh,K. (2009). Principles of Experimental Research. Butterworth-Heinemann.