Question 1085939: In a study examining the effect of alcohol on reaction time, Liguori and Robinson (2001) found that even moderate alcohol consumption significantly slowed response time to an emergency situation in a driving simulation. In a similar study, researchers measured reaction time 30 minutes after participants consumed one 6-ounce glass of wine. Again, they used a standardized driving simulation task for which the regular population averages m = 400 msec. The distribution of reaction times is approximately normal with a = 40. Assume that the researcher obtained a sample mean of M = 422 for the n = 25 participants in the study.
Are the data sufficient to conclude that the alcohol has a significant effect on reastion time? Use a two tailed test with a=0.01
For this sample, the standard error is ______, and the value of the z-score is _____. With a=0.01, the boundaries of the critical region are _____. therefor, the data ______ sifficient to conclude that alcohol has significant effect on reaction time.
Does the data provide evidence that the alcohol significantly increased (slowed) reaction time? Use a one-tailed test with a=0.05
The data _____ provide evidence that the alcohol significantly (slowed) reaction time as the value of the z-score is _______ the boundary of the critical region of _____ obtained using one tailed test with a=0.05
Compute cohens d to estimate the size of the effect
cohen's d =
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! SE=s/ sqrt(n). I am assuming a=40 is std dev=40
40/sqrt(25)=8, the standard error
z-score is (422-400)/8=22/8=2.75
with alpha=0.01, for a two sided test, z=+/-2.576
The boundaries are 8*2.576=20.608
Critical value or 99%CI=(379.392, 420.608)
The data fall outside the boundaries providing evidence that alcohol significantly increased the reaction time.
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with alpha=0.05, use 1.645, since it is one tail
now the upper boundary is 8*1.645+400=413.16
Now the evidence is insufficient to show that there was a difference.
d=(M1-M2)/s=22/8=2.5
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