Question 1112813
1)  standard error(SE) of proportion = square root(0.61 * (1-0.61) / 140) = 0.04
:
test statistic z = (0.65 - 0.61) / 0.04 = 1
:
this is an upper one-tailed test for alpha = 0.05
:
critical z-score = 1.645
:
since the test statistic is < 1.645, we select answer A
:
2) this is a lower one-tailed test
:
test statistic z = 1
critical z-score = -1.645
:
since the test statistic is < 1.645, we select answer B
:
3) this is a two-tailed test, alpha = 0.05/2
:
test statistic z-score = (0.55 - 0.61) / 0.04 = -1.5
:
positive critical z-score = 1.960
negative critical z-score = -1.960
:
since test statistic is > -1.960, we select answer A