Hi everyone, I need help in how to determine the small, medium and large sample size for correlation coefficients? is there any reference or journal about that? Thanks in advanced!
I have not heard small, medium or large sample size definitions but effect sizes.
There are lots of resources on net about finding sample size for correlation coefficient. Some follows
Cohen J (1988) Statistical Power Analysis for the Behavioral Sciences
Machin D, Campbell MJ,Tan SB, Tan SH Sample Size Tables for Clinical Studies
http://stats.stackexchange.com/questions/15842/what-is-a-reasonable-sample-size-for-correlation-analysis-for-both-overall-and-s
http://stats.stackexchange.com/questions/154478/sample-size-calculation-for-correlation-study
http://www.r-bloggers.com/at-what-sample-size-do-correlations-stabilize/
Have a look of the site:
http://www.sample-size.net/correlation-sample-size/
Reference: Hulley SB, Cummings SR, Browner WS, Grady D, Newman TB. Designing clinical research : an epidemiologic approach. 4th ed. Philadelphia, PA: Lippincott Williams & Wilkins; 2013. Appendix 6C, page 79.
Hi,
if you are SAS user, you can use simple code
proc power;
onecorr dist=t
TEST=PEARSON
corr = 0.40
ntotal = .
ALPHA=0.05
power = 0.90;
run;
You need more data if you would like to prove weak correlation as statistically significant (e.g. corr = 0.20) than if you would like to prove as significant strong correlation (e.g. corr = 0.80).
See https://support.sas.com/documentation/cdl/en/statug/63033/HTML/default/viewer.htm#statug_power_sect005.htm for details (if you have SAS software available)
BR Lada
Dear Nur
You can use G*Power software to calculate sample size for correlation or any other experiment, G*Power is free to download and easy to use after reading the manual, the download link:
http://download.cnet.com/G-Power/3000-2054_4-10647044.html
The link to download G*Power manual:
http://www.gpower.hhu.de/fileadmin/redaktion/Fakultaeten/Mathematisch-Naturwissenschaftliche_Fakultaet/Psychologie/AAP/gpower/GPowerManual.pdf
Good Luck
Dear RG colleague,
Determining the sample sizes involve resource and statistical issues. Usually, researchers regard 100 participants as the minimum sample size when the population is large. However, In most studies the sample size is determined effectively by two factors: (1) the nature of data analysis proposed and (2) estimated response rate.
For example, if you plan to use a linear regression a sample size of 50+ 8K is required, where K is the number of predictors. Some researchers believes it is desirable to have at least 10 respondents for each item being tested in a factor analysis, Further, up to 300 responses is not unusual for Likert scale development according to other researchers.
Another method of calculating the required sample size is using the Power and Sample size program (www.power-analysis.com).
Regards,
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