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1 / 7 Practice Test 1 Business Statistics: Multiple Choice: Each is worth two pointsIdentify the letter of the choice that best completes the statement or answers the question.**Skip 15-17,18,20 Ch10-12,13 Material ____ 1. The sum of the relative frequencies 频率 for all classes will always equal a. the sample size b. the number of classes c. one d. any value larger than one ____ 2. The interquartile range 四分位差 is a. the 50th percentile b. another name for the variance c. the difference between the largest and smallest values d. the difference between the third quartile and the first quartile ____ 3. The standard deviation 标准偏差 of a sample of 100 observations观察值 equals 64. The variance of the sample equals a. 8 b. 10 c. 6400 d. 4,096 ____ 4. The numerical value 数值 of the standard deviation can never be a. larger than the variance b. Zero c. Negative d. smaller than the variance ____ 5. The set of all possible sample points (experimental outcomes) is called a. a sample b. an event c. the sample space d. a population ____ 6. A random variable 随机变量 that can assume假设 only a finite 有限 number of values is referred to as a(n) a. infinite sequence b. finite sequence c. discrete random variable d. discrete probability function Exhibit 展示 5-11 A local bottling 瓶装 company has determined the number of machine breakdowns per month and their respective probabilities as shown below: Number of Breakdowns Probability 0 0.12 1 0.38 2 0.25 3 0.18 4 0.07 ____ 7. Refer to Exhibit 5-11. The probability of at least 3 breakdowns in a month is？？？？a. 0.5 b. 0.10 c. 0.30 d. 0.90 ____ 8. A normal probability distribution概率分布a. is a continuous probability distribution b. is...