An experiment is conducted to determine if 30 minutes of exercise per day
reduces systolic blood pressure. For subjects who are assigned to exercise, change
in systolic blood pressure
(X)
is recorded. A positive value of
X
indicates that an
increase in systolic blood pressure was observed.
(a) Assume that changes in systolic blood pressure follow a normal distribution
and that
Í =
25 and s = 12. Find
?ô[×
-4.8] under
H0:
No effect of 30
minutes of exercise per day on blood pressure.
(b) The researchers will consider the results "significant" if
X/(s/y/n)
ß ï
. è 5 , ç
- é
For a sample size of 121, what is the probability that the results will be considered
"significant" if
X
actually has a mean of -0.673 and
s =
12?
(c) Is the hypothesis test in (b) a one-sided or two-sided test?
(d) If
X
was observed to be 2.5, would the researchers consider the results "significant"?