Q24. A study is under way in Yosemite National Forest to determine the adult height of American pine trees. Specifically, the study is attempting to determine what factors aid a tree in reaching heights greater than 60 feet tall. It is estimated that the forest contains 25,000 adult American pines. The study involves collecting heights from 250 randomly selected adult American pine trees and analyzing the results. Identify the population from which the study was sampled. a. The 250 randomly selected adult American pine trees in the forest. b. The 25,000 adult American pine trees in the forest. c. All the adult American pine trees taller than 60 feet in the world. d. All American pine trees, of any age, in the forest. Q25. Major league baseball salaries averaged $1.5 million with a standard deviation of $0.8 million in 1994. Suppose a sample of 100 major league players was taken. Find the approximate probability that the average salary of the 100 players exceeded $1 million. a. Approximately 0 b. Approximately 0.257 c. Approximately 0.736 d. Approximately 1 Q26. Selection of raffle tickets from a large bowl is an example of: a. sampling with replacement. b. sampling without replacement. c. subjective probability. d. None of the above. Q27. Which of the following statements about the median is not true? a. It is more affected by extreme values than the mean. b. It is a measure of central tendency. c. It is equal to Q2. d. It is equal to the mode in bell-shaped “normal” distributions. Q28. In left-skewed distributions, which of the following is the correct statement? a. The distance from Q1 to Q2 is smaller than the distance from Q2 to Q3. b. The distance from the smallest observation to Q1 is larger than the distance from Q3 to the largest observation. c. The distance from the smallest observation to Q2 is smaller than the distance from Q2 to the largest observation. d. The distance from Q1 to Q3 is twice the distance from Q1 to Q2. Q29. A catalog company that receives the majority of its orders by telephone conducted a study to determine how long customers were willing to wait on hold before ordering a product. The length of time was found to be a random variable best approximated by an exponential distribution with a mean equal to 3 minutes. What proportion of customers having to hold more than 1.5 minutes will hang up before placing an order? a. 0.86466 b. 0.60653 c. 0.39347 d. 0.13534 Q30. A lab orders 100 rats a week for each of the 52 weeks in the year for experiments that the lab conducts. Suppose the mean cost of rats used in lab experiments turned out to be $13.00 per week. Interpret this value. a. Most of the weeks resulted in rat costs of $13.00. b. The median cost for the distribution of rat costs is $13.00. c. The expected or average cost for all weekly rat purchases is $13.00. d. The rat cost that occurs more often than any other is $13.00. Q31. If two equally likely events A and B are mutually exclusive and collectively exhaustive, what is the probability that event A occurs? a. 0 b. 0.50 c. 1.00 d. Cannot be determined from the information given. Q32. The chancellor of a major university was concerned about alcohol abuse on her campus and wanted to find out the portion of students at her university who visited campus bars every weekend. Her advisor took a random sample of 250 students. The portion of students in the sample who visited campus bars every weekend is an example of a __________. a. categorical random variable b. discrete random variable c. parameter d. statistic Q33. Why is the Central Limit Theorem so important to the study of sampling distributions? a. It allows us to disregard the size of the sample selected when the population is not normal. b. It allows us to disregard the shape of the sampling distribution when the size of the population is large. c. It allows us to disregard the size of the population we are sampling from. d. It allows us to disregard the shape of the population whennis large. Q34. A population frame for a survey contains a listing of 6,179 names. Using a table of random numbers, which of the following code numbers will appear on your list? a. 06 b. 0694 c. 6946 d. 61790 Q35. Which of the mean, median, mode, and geometric mean are resistant measures of central tendency? a. The mean and median. b. The median and mode. c. The mode and geometric mean. d. The mean and mode.