3. A political campaign manager wants to test the effectiveness of a new advertisement featuring Candidate X The campaign manager takes a random sample of 300 voters before the ad goes on air and another random
sample of 250 voters afterwards. 158 of the 300 voters in the "before" sample say they support Candidate X
and 140 voters in the “after” sample say they support Candidate X. If P,= the proportion of all voters who
support Candidate X after the ad is aired and Pe=the proportion of all voters who support Candidate X
before the ad is aired, which of the following is the correct standardized test statistic for H: P.-P. = 0?
0.56 -0.527
0.56 -0.527
(b)
10.56(0.44 0.527(0.473)
0.542(0.458) 0.542(0.458)
250
300
250
300
0.56 -0.527
0.56 -0.527
(c) == -
(d)
0.542(0.458)
0.56(0.44) 10.527(0.473)
550
250
300
0.56 -0.527
(e) ==
0.56 0.527
250 300