The January 2005 Gallup Youth Survey telephoned a random sample of 1,028 U.S. teens and asked these teens to name their favorite movie from 2004.
Napoleon Dynamite had the highest percentage with 8 of teens ranking it as their favorite movie. Which is true?
I. The population of interest is all U.S. teens.
II. 8 is a statistic and not the actual percentage of all U.S. teens who would rank this movie as their favorite.
III. This sampling design should provide a reasonably accurate estimate of the actual percentage of all U.S. teens who would rank this movie as their favorite.
A) I only B) I and II C) III only D) II only E) I, II, and III
Q. 2The mean monthly gasoline bill for one household is greater than 150. If a hypothesis test is performed, how should you interpret a decision that fails to reject the null hypothesis?
A) There is not sufficient evidence to reject the claim > 150.
B) There is sufficient evidence to reject the claim > 150.
C) There is sufficient evidence to support the claim > 150.
D) There is not sufficient evidence to support the claim > 150.
Q. 3A local outdoor equipment store is being sold. The buyers are trying to estimate the percentage of items that are outdated. They will randomly sample among its 100,000 items in order to determine the proportion of merchandise that is outdated.
The current owners have never determined their outdated percentage and can not help the buyers. Approximately how large a sample do the buyers need in order to insure that they are 90 confident that the margin of error is within 3?
A) 3007 B) 752 C) 1504 D) 457
Q. 4Suppose an experiment consists of selecting two smoke detectors from a large shipment. Let the events be:
A: The first detector is not defective,
B: The second detector is defective.
Are A and B mutually exclusive events?
A) no B) yes C) cannot be determined
Q. 5The tread life of a particular brand of tire is a random variable best described by a normal distribution with a mean of 60,000 miles and a standard deviation of 1800 miles.
What is the probability a certain tire of this brand will last between 56,220 miles and 56,760 miles?
A) 0.4649 B) 0.4920 C) 0.0180 D) 0.9813
Q. 6The random variable x represents the number of girls in a family of three children. Assuming that boys and girls are equally likely, find the mean and standard deviation for the random variable x.
A) mean: 1.50; standard deviation: 0.87 B) mean: 2.25; standard deviation: 0.76
C) mean: 1.50; standard deviation: 0.76 D) mean: 2.25; standard deviation: 0.87
Q. 7A/An __________ is a subset of data selected from a population.
A) variable B) experimental unit C) statistic D) sample
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