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Lecture 1, in class practice 1.In a sample of 1,000 students in a university, 125 of them or 12.5% are biology majors. The 12.5% is an example of statistical inference. ANS: F 2. Individual observations within each class may be found in a frequency distribution. ANS: F 3. Twenty-five percent of a sample of 200 professional tennis players indicated that their parents did not play tennis. This is an example of descriptive statistics, rather than inferential statistics. Ans: T 4. Suppose you are given a graphical portrayal of a relative frequency distribution of continuous quantitative data with the following characteristics. The lower and upper limits of the data classes are identified by tick marks on a horizontal axis. The corresponding relative class frequencies are represented by the areas of vertical rectangles connected to each other and positioned on top of each of these class intervals. What is such a graphical presentation called? a. a stacked bar chart b. a Pareto chart c. a pictogram d. a relative frequency histogram ANS: D 5. .A histogram is often used to portray various characteristics of a quantitative variable. Which characteristics is it usually used to display? a. the spread or variability in the data b. the approximate centre of the data c. both (a) and (b) ANS: C 6. Which of the following are displayed using a bar chart? a. time series data b. continuous variables c. qualitative variables d. quantitative variables ANS: C 7. A stem-and-leaf plot is used to display the distribution of which of the following kinds of data? a. qualitative data b. quantitative data c. two quantitative variables on the same chart d. bivariate data ANS: B TOP: 4–5 8. If the manager of a grocery store wishes to display the sales trend, which of the following is the most effective type of graph to use? a. a bar chart b. a pie chart c. a histogram d. a line chart ANS: D Consider all the cheeses produced in the world. Suppose 75% of them are aged less than 2 years. A sample of 20 cheeses are obtained from around the world. a)Describe the population and sample of the problem. b) Write a probability question and a statistics question involving the population and sample.