Answer:
C. 2.937
Explanation:
Given the following :
H0 : p = 0.25
H1 : p > 0.25
Number of observations (n) = 647
p' = 30% = 0.3
SD = sqrt[(p(1 - p) / n)]
1 - p = 1 - 0.25 = 0.75
SD = sqrt[(0.25 * 0.75) / 647]
SD = sqrt[0.0002897]
SD = 0.0170234
Z = (p' - p) / SD
Z = (0.3 - 0.25) / 0.0170234
Z = 0.05 / 0.0170234
Z = 2.9371187 = 2.937