Given a distribution that follows a standard normal curve, what does the graph of the curve do as z increases in the positive direction?
A) The graph of the curve approaches zero.
B) The graph of the curve approaches an inflection point.
C) The graph of the curve approaches 1.
D) The graph of the curve eventually intersects the horizontal axis.
Q. 2A survey of students at one college found that 75 of 112 randomly selected freshmen and 88 of 117 randomly selected sophomores lived off campus.
Find a 98 confidence interval for the difference between the proportions of freshmen and sophomores at this college who live off campus.
A) 0.531 to 0.809 B) 0.553 to 0.787 C) -0.200 to 0.787 D) -0.222 to 0.057
Q. 3A drug company claims that over 90 of all physicians recommend their drug. 400 physicians were asked if they recommend the drug to their patients. 56 said yes. H0: p = 0.9.
A) -29.467 B) -45.334 C) -20.400 D) -22.667
Q. 4Which of the following statements concerning the standard normal curve is/are true (if any)?
a. The area under the standard normal curve to the left of -3 is zero.
b. The area under the standard normal curve between any two z-scores is greater than zero.
c. The area under the standard normal curve between two z-scores will be negative if both z-scores are negative.
d. The area under the standard normal curve to the left of any z-score is less than 1.
A) a, c B) b, d C) a, b D) a
Q. 5A highly selective boarding school will only admit students who place at least 1.5 z-scores above the mean on a standardized test that has a mean of 110 and a standard deviation of 12.
What is the minimum score that an applicant must make on the test to be accepted?
A) 98 B) 92 C) 128 D) 122
Q. 6When the effects of the explanatory variable upon the response variable cannot be determined, then
A) the claim is invalid. B) confounding has occurred.
C) a lurking variable is present. D) there is sampling error.
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