In some experiments where we use ANOVA some of the unexplained variability (i.e. the error) is due to some additional variable (called a covariate) which is not part of the experiment. If we can somehow remove the effect of this variable, we could reduce the error variance thus enabling us to get a more accurate picture of the true effect of the independent variable. This is the main goal of Analysis of Covariance (ANCOVA).
Topics
- Basic concepts
- Regression approach
- Assumptions
- ANOVA approach
- Contrasts
- Tukey’s HSD and Tukey-Kramer
- Effect Size
- Conversion to Stacked Format
- Real Statistics Data Analysis Tools
- Pretest-Posttest Design
- When homogeneity of slopes assumption is violated
References
Howell, D. C. (2010) Statistical methods for psychology (7th ed.). Wadsworth, Cengage Learning.
https://labs.la.utexas.edu/gilden/files/2016/05/Statistics-Text.pdf
Schmuller, J. (2009) Statistical analysis with Excel for dummies. Wiley
https://www.wiley.com/en-us/Statistical+Analysis+with+Excel+For+Dummies%2C+3rd+Edition-p-9781118464311
I am comparing between microorganism in different temperature 20& 25 C and I have two factors weights and producing young which analyses will work Charles please. Thank you in advance
Hello Mo,
What is your question? What hypothesis are you trying to test?
Charles
Charles,
How to perform maximum covariance analysis (MCA) between two time series using real-stat to obtain squared covariance factor (SCF) etc. ? Thank you.
Hello Amit,
I haven’t yet investigated this issue. Do you have a good reference that I could use?
Charles
Dear Charles,
I found 2 references. Please find below.
https://doi.org/10.1175/1520-0426(2003)020%3C1804:EAFMCA%3E2.0.CO;2
https://doi.org/10.1175/1520-0442(1992)005%3C0541:AIOMFF%3E2.0.CO;2
Which statistical procedure will be applied in this research work ? title is “COMPARATIVE EFFECT OF THREE TYPES AEROBIC TRAINING ON SELECTED PHYSIOLOGICAL AND ANTHROPOMETRIC VARIABLES OF TRIBAL BOYS”
please inform it. thanks.
Avijit,
You need to provide more information for me to be able to respond to your question.
Charles
Great Thank you very much
Sir, is it possible to incorporate Cochran’s Q test and time series analysis to enrich your already rich website. Thank you in advance.
Good idea. I will include Cochran’s Q test in the next release. Time series analysis will have to come a bit later.
Charles