Neuroscience researchers did a study of thirty college-age subjects. 10 particip
ID: 3023916 • Letter: N
Question
Neuroscience researchers did a study of thirty college-age subjects. 10 participants received one of the following beverages: water, water plus caffeine, or water plus caffeine plus sugar.Participants underwent two MRI scans and also took a performance test. On the performance test, the water group scored 29.00 with a standard error of 1.33. The caffeine group scored 30.70with a standard error of1.33. The caffeine plus sugar group scored 30.75with a standard error of1.49.So N=10 for each group.
Create a 90% confidence interval for the caffeine group, using a table value of 1.645. The confidence interval is (Blank 1, Blank 2). Use three decimal places for your answers.
Explanation / Answer
Note that
Lower Bound = X - z(alpha/2) * se
Upper Bound = X + z(alpha/2) * se
where
alpha/2 = (1 - confidence level)/2 = 0.05
Thus,
X = sample mean = 30.7
z(alpha/2) = critical z for the confidence interval = 1.645
se = standard error = 1.33
Thus,
Lower bound = 28.51215
Upper bound = 32.88785
Thus, the confidence interval is
( 28.512 , 32.888 ) [ANSWER]