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Math 20-2 Statistics Statistics Exam Review Examples Please see the Statistics Review Checklist for a comprehensive list of all the skills you need to remember for the exam. Let’s do these examples as a quick review of some of the most important skills: 1. Emmanuela walks her golden retriever regularly. She kept track of the lengths of her walks for one month and grouped the data in a frequency table. Length of Walk (min) 5-10 10-15 15-20 20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 Frequency 1 3 7 10 6 11 8 5 4 2 3 a) What is the mode of this data? b) Use your calculator to find the mean, median, standard deviation, and range for the length of Emmanuela’s dog walks. Round to the nearest tenth. 2. In a survey, it was reported that 78.8% - 83.2% of Canadians support bilingualism in Canada. This poll was reported accurate 97 times out of 100. a) What is the confidence level of this survey, as a percent? b) If the population of Canada is 35.3 million people, what is the confidence interval in number of people who support bilingualism? Round to the nearest tenth of a million people. c) What is the margin of error of this survey, as a percent? Math 20-2 Statistics 3. A lower standard deviation means that the data is __________ spread out or __________ consistent. Which of the following normal curves has the lowest standard deviation? A. B. C. 4. In a recent survey of students at a particular high school, it was determined that the heights of students were normally distributed with a mean of 171 cm and a standard deviation of 6.5 cm. a) Amy is 159 cm tall. What is the z-score of her height, to the nearest hundredth? What does this mean? b) If there are 768 students in the school, how many of them are shorter than Amy? c) Patrick’s height has a z-score of 0.31. How tall is he, to the nearest centimetre? d) How tall would you have to be to be in the tallest 7% of students in the school? Round to the nearest centimetre. Math 20-2 Statistics 5. Things to remember when drawing graphs: In General Histograms Frequency Polygons Now make sure you spend some time doing some practice questions on your own! - Statistics Review - Textbook questions p. 308-310 (Use the Statistics Review Checklist to decide which questions to focus on.)