A resercher plans to conduct an experiment evaluating the effect of a treatment. A sample of n=9 participants is selected and each person receive the treatment before being tested on a standardized dexterity task. The treatment is expected to lower scores on the test by an average of 30 points. For the regular population, scores on the dexterity task form a normal distribution with u=240 and o=30. a)If the researcher uses a two-tailed test with a=.05, what is the power of the hypothesis test ?

b)Again assuming a two-tailed test with a=.05, what is the power of the hypothesis test

Sample size 9

30 (on average how much lower)

Does each increase, decrease or stay the same Assume all other factors are held constant

the size of the Z-score

The size of cohen's D

The power P