A national chain of department stores ranks its 1,250,000 salespeople by the monetary value of their sales. Chang's sales are at the 69L" percentile. Jina's sales are at the 58th percentile. (If necessary, consult a list of formulas.) (a) which of the following must be true about Chang's sales? X \\(3 '3 0 Chang had sales lower in value than about 69% of the salespeople. O The value of Chang's sales were about 69% of the chain's total. ' Undo ' 0 Chang had sales higher in value than about 69% of the salespeople. ' I O The value of Chang's sales were about 31% of the chain's total. Message Center > (b) Which of the following must be true about Chang's and Jina's sales? 0 Jina's sales were higher in value than Chang's sales. 0 Both Chang and Jina had sales higher in value than the median. O The value of Chang's sales were $1100 more than Jina's. O The values of both Chang's and Jina's sales were in the bottom half of all of the salespeople. (a) A chemist at a pharmaceutical company wants to test the quality of a new batch of microscopes. which of the following best describes a systematic sample of microscopes? O The chemist assigns each microscope a different number. Using a random number table, he draws 80 of those numbers at random. Then, he selects the microscopes assigned to the drawn numbers. Every set of 80 microscopes is equally likely to be drawn using the random number table. 0 The chemist forms 4 groups of microscopes based on the prices of the microscopes. Then, he selects 20 microscopes at random from each group. O The chemist takes a list of the microscopes and selects every 4th microscope until 80 microscopes are selected. (b) Counselors at a college want to poll students about how much time the students spend studying. Which of the following best describes a convenience sample of students? 0 The students living in a particular dorm building on campus are easily accessible. So, the counselors select the 56 students living in that particular dorm building. 0 The counselors use a computer program to draw 56 students at random and select these students. Every set of 56 students is equally likely to be drawn by the computer program. 0 The counselors take a list of the students and select every 7th student until 56 students are selected. (c) 111s organizers of a conference want to survey attendees about the registration fee. Which of the following best describes a stratied sample of attendees? O The organizers form groups of 30 attendees based on the day the attendees registered. Then, the organizers randomly choose 3 groups and select all of the attendees in these groups. 0 The organizers form 5 groups of attendees based on the attendees' employment statuses. Then, the organizers select 18 attendees at random from each group. O The organizers select the rst 90 attendees who register for the conference because these attendees are easily accessible