If you're having trouble solving homework problems, must you sleep on it and try again in the morning? Huber asked 10 human subjects to carry out a complex spatial learning task on computer just before going to sleep. EEG recordings were then taken of electrical activity of brain cells throughout their sleep. The magnitude of the raise in their "slow-wave" sleep after learning the complex task, compared to baseline amounts, is listed in accompanying table for all 10 subjects. Also provided is the raise in performance recorded when the subjects were challenged with same task upon waking.
Increase in slow-wave Improvement in task performance activity throughout sleep (percent) after waking (percent)
8 8
14 3
13 0
15 0
17 8
18 15
31 14
32 10
44 27
54 26
A) Compute the correlation coefficient between magnitude of increase in slow-wave sleep and the magnitude of the improvement in performance up waking.
B) Determine the standard error for your estimate in part a?
C) Give an interpretation of the quantity you calculated in part b. what does it measure?
D) Test the hypothesis that two variables are correlated in the population
E) Us this an observational or experimental study? why?