which is the independent variable and dependent variable

#1
I am exploring the association between sleep and vigilance. I am doing a study which tests the relationship between self-reported hours of sleep, self-reported sleepiness rating, and performance on a test of vigilance called the psychomotor vigilance task (we measured lapses. Lapses = the number of times participants took more than 500ms to respond to the stopwatch. Fewer lapses = better performance).

would the independent variable be self-reported hours of sleep, and the dependent variables be sleepiness rating and lapses?

Additionally, would spearman’s rho be the appropriate statistical test to use?
 

Karabiner

TS Contributor
#2
I am exploring the association between sleep and vigilance.
would the independent variable be self-reported hours of sleep, and the dependent variables be sleepiness rating and lapses?
Well, this depends on your research question(s) and on your theoretical model.
Are you really interested in the relationship between hours of sleep and sleepiness?
And/or did you have something in mind like hours of sleeep -> sleepiness -> task performance?

Additionally, would spearman’s rho be the appropriate statistical test to use?
It can be used here, but whether it is the best solution, again depends on your research
question(s) .

With kind regards

Karabiner
 
#3
Thank you that has me thinking, so I should be measuring the relationship between hours of sleep and lapses. And measuring the relationship between sleepiness rating and lapses
 
#4
Additionally, would this be a correct written interpretation of spearman’s rho?

Spearman’s rho correlation was computed to assess the relationships between hours slept, sleepiness rating, and lapses. Despite a weak negative correlation there was no significant relationship between hours slept and lapses, r(424) = -.076, p = .120. There was a statistically significant, weak positive correlation between sleepiness rating and lapses, r(424) = .132, p = .006. There was a statistically significant, moderate negative correlation between sleepiness rating and hours slept, r(424) = -.255, p = <.001
 
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