Answers for Chapter 3 Masters

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1 Answers for Chapter 3 Masters Scaffolding Answers Scaffolding for Getting Started Activity (Master) p. 55 D. For example, Comparing the Number of Cubes Removed by Each Method 3 Number of cubes Kayley s Method Kito s Method E. For example, almost all of the bars representing Kito s method have a higher value than the bars representing Kayley s method. This means he removed more cubes than Kayley. Scaffolding for Do You Remember? (Master) pp a) Stem Leaf b) The mark range is from 46 to 93. Most students get a mark in 8s. A few students get low marks below 7 and a few students get high marks above 9. One person failed the assignment. 6. The mean is found by adding all the numbers in the series and dividing by 8. the mean of the set of data = ( ) 8 = = 23 The median of the set of data is the number in the middle. The data in order from least to greatest is 9, 15, 17, 17, 18, 22, 33, 53. The highlighted numbers indicate where the middle of the data is. median = ( ) 2 = 17.5 The mode is the most frequent value of the set of data. The mode is Chapter 3: Collecting, Organizing, and Displaying Data Copyright 26 by Thomson Nelson

2 Scaffolding for Lesson 3.4 (Master) p a) 11.8, 12.3, 12.4, 12.7, 12.8, 12.9, 13.1, 13.1, 13.4, 13.7, 13.7, 13.8, 13.8, 13.8, 13.9, 13.9, 13.9, 13.9, 14., 14.2, 14.3, 14.3, 14.4, 14.4, 14.4, 14.4, 14.5, 14.5, 14.7, 14.8, 14.8, 15., 15.2, 15.4 The range is 3.6. If I use three intervals, the interval ranges would be 1.6. If I use five intervals, the interval range would be 1. b) Five intervals are better because three are two few. c) Times Recorded for a 1 m Race Frequency Chapter Test (Master) pp Answers 1. a) For example, Students Cherry Lord Pirates The Reebots Cotter of the of the Fabulites Loops Pacific Saw the movie Read the book b) For example, with a double bar graph, I can compare side by side the number of students who saw the movie with the number who read the book. c) Yes, I think it would be because Grade 8 to 12s all like these kinds of movies, but it would be better to take a sample from each grade. 2. For example, sometimes it s not physically possible to collect information from every single person in the population. It also might cost too much money or take too much time. If you have a good sized, representative sample, you can get close to the information from the whole population // Distance Students Threw a Discus / 3 31 // / // / / / Time (second) Number of students //// / Distance (m) // 39 4 / Copyright 26 by Thomson Nelson Chapter 3 Answers 65

3 4. a) b) c) d) 126 e) The mean changed to 133. The mode and median did not change.the mean was most affected. Removing the highest and lowest values does not change the median or the mode. The middle value will still be the middle value, but in a shorter list of data, and the most frequent value will still be 126. Because the lowest value was quite a bit lower than the rest of the data, when it was removed the mean increased. Chapter 3 Task Pages 1 & 2 (Master) pp A. For example, 1. Record the height of each student. 2. Record the arm length of each student. 3. Record the leg length of each student. 4. Find the average of three vertical jumps of each student. 5. Compare the average vertical jump of each student to their height, arm length, and leg length and write your conclusion. B. Student Height Arm Length Leg Length John Alyssa Medhat Johan Rene Mila Agnes C. Student Jump Length Jump Length Jump Length Average John Alyssa Medhat Johan Rene Mila Agnes Chapter 3: Collecting, Organizing, and Displaying Data Copyright 26 by Thomson Nelson

4 D. I decided to make scatter plots to compare my data. Height of Jumper Height of jumper (cm) The best predictor of vertical jumping is either the height, arm length or leg length, because the tallest people also have the longest arms and legs. The tallest people jump the highest. Answers to Key Assessment of Learning Question, Lesson 5 (continued from p. 35) 9. a) The four marks whose removal would lower the mean score the most is the four greatest marks: 7.25, 7., 6.75, mean of the 7 marks = ( ) 7 = = 6.25 Since there are only 7 marks left, the median is the fourth number of the 7 marks, which is b) The four marks whose removal would raise the mean score the most are the four lowest marks: 5.75, 6., 6.25, mean of the 7 marks = ( ) 7 = = 6.75 Since there are only 7 marks left, the median is the fourth number of the 7 marks, which is Answers to Chapter Self-Test (continued from p. 42) 5. a) Use a stem-and-leaf plot to organize the data. Arm Length Arm length (cm) Leg Length Leg length (cm) Stem Leaf The median is 13 C. Calculate the mean by adding all the temperatures, and dividing by 3. mean = ( ) 3 = = The mean is about 13.9 C for April. The mode is 12 C for April. Copyright 26 by Thomson Nelson Chapter 3 Answers 67

5 b) Use another stem-and-leaf plot to organize the data after removing the three greatest and least values. Stem Leaf The median is 13 C. Calculate the mean by adding all the temperatures, and dividing by 24. mean = ( ) 24 = = The mean is about 13.5 C for April. The mode is 12 C for April. Since the median and mode do not change, the median was the most affected. It dropped by.4 C. 68 Chapter 3: Collecting, Organizing, and Displaying Data Copyright 26 by Thomson Nelson