NAME DATE PERID Stud Guide and Intervention A scatter plot is a graph that shows the relationship between two sets of data. In a scatter plot two sets of data are graphed as ordered pairs on a coordinate sstem. A scatter plot ma show a pattern or relationship of the data. The relation ma be positive or negative, or there ma be no relationship. Eample SCHL The table shows Miranda s math quiz scores for the last five weeks. Make a scatter plot of the data. Since the points are showing an upward trend from left to right, the data suggest Week Score 1 2 51 3 65 Miranda's Quiz Scores Score 60 4 72 5 40 30 1 2 3 4 5 6 Week Eercises FD For Eercises 1 3, use the table below which shows the fat grams and calories for several snack foods. Food Fat grams Calories per serving per serving doughnut 13 306 corn chips 13 200 pudding 3 1 cake 13 230 snack crackers 6 140 ice cream (light) 5 130 ogurt 2 Calories 400 3 300 2 200 1 Snack Food Data 3 6 9 12 15 18 21 Fat (grams) cheese pizza 18 410 1. Make a scatter plot of the data in the table. 2. What do the -coordinates represent? -coordinates? 3. Is there a relationship between fat and calories? Eplain. Glencoe/McGraw-Hill 31 Glencoe Pre-Algebra
NAME DATE PERID Skills Practice Tell whether each scatter plot shows a positive, negative, or no relationship. 1. 2. 3. 4. Draw a scatter plot with si ordered pairs that shows Eplain our reasoning. For Eercises 5 8, use the following information: SCIENCE Scientists have determined that there ma be a relationship between temperature and the number of chirps produced b crickets. The table gives the temperature and the number of chirps per minute for several cricket samples. 5. Make a scatter plot of the data. 6. Does there appear to be a relationship between temperature and chirps? Eplain. Temperature ( F) Chirps/min 71 138 68 97 75 152 158 60 81 75 155 84 165 7. Suppose the outside temperature is 65 o. About how man chirps per minute would ou epect from a cricket? 8. Suppose the outside temperature is 55 o. About how man chirps per minute would ou epect from a cricket? Chirps/min 1 160 1 140 130 120 110 55 60 65 75 85 Temperature ( F) Glencoe/McGraw-Hill 32 Glencoe Pre-Algebra
NAME DATE PERID Practice Determine whether a scatter plot of the data for the following might show a positive, negative, or no relationship. 1. a person s jogging speed and time spent jogging 2. the size of a famil and the weekl grocer bill 3. the size of a car and the cost 4. a person s weight and percent bod fat 5. time spent plaing video games and time spent on outdoor activit 6. Draw a scatter plot with ten ordered pairs that shows a negative relationship. EMPLYMENT For Eercises 7 9, use the table below, which shows the median salar for women who had completed a college degree for the ears 1989 1998. Salar in Thousands of Dollars 1989 42 19 43 1991 45 1992 46 1993 48 1994 49 1995 1996 51 1997 53 1998 57 7. Make a scatter plot of the data. Salar (in thousands) 56 54 52 48 46 44 42 Median Salar 1989-1998 '89 '91 '93 '95 '97 '99 Source: Time Almanac 8. Does there appear to be a relationship between ear and salar? 9. Based on the graph, predict what the median salar was for the ear 2000. Glencoe/McGraw-Hill 33 Glencoe Pre-Algebra
Answers () NAME DATE PERID Skills Practice Tell whether each scatter plot shows a positive, negative, or no relationship. 1. 2. 3. none negative positive 4. Draw a scatter plot with si ordered pairs that shows Eplain our reasoning. See students answers. For Eercises 5 8, use the following information: SCIENCE Scientists have determined that there ma be a relationship between temperature and the number of chirps produced b crickets. The table gives the temperature and the number of chirps per minute for several cricket samples. Temperature ( F) Chirps/min 71 138 68 97 75 152 158 5. Make a scatter plot of the data. 60 81 6. Does there appear to be a relationship between temperature and chirps? Eplain. Yes, as temperature increases, chirps/min increase indicating a positive relationship. Chirps/min NAME DATE PERID Stud Guide and Intervention A scatter plot is a graph that shows the relationship between two sets of data. In a scatter plot two sets of data are graphed as ordered pairs on a coordinate sstem. A scatter plot ma show a pattern or relationship of the data. The relation ma be positive or negative, or there ma be no relationship. Eample SCHL The table shows Miranda s math quiz scores for the last five weeks. Make a scatter plot of the data. Since the points are showing an upward trend from left to right, the data suggest Week Score 1 Miranda's Quiz Scores 60 Week Eercises FD For Eercises 1 3, use the table below which shows the fat grams and calories for several snack foods. Glencoe/McGraw-Hill 31 Glencoe Pre-Algebra 7. Suppose the outside temperature is 65 o. About how man chirps per minute would ou epect from a cricket? about 110 chirps 8. Suppose the outside temperature is 55 o. About how man chirps per minute would ou epect from a cricket? about chirps 75 155 84 165 1 160 1 140 130 120 110 55 60 65 75 85 Temperature ( F) Glencoe/McGraw-Hill 32 Glencoe Pre-Algebra Score 2 51 3 65 4 72 5 40 30 1 2 3 4 5 6 Food Fat grams Calories per serving per serving doughnut 13 306 Snack Food Data corn chips 13 200 Calories 400 3 pudding 3 1 cake 13 230 snack crackers 6 140 ice cream (light) 5 130 ogurt 2 300 2 200 1 3 6 9 12 15 18 21 Fat (grams) cheese pizza 18 410 1. Make a scatter plot of the data in the table. 2. What do the -coordinates represent? -coordinates? -coordinates: fat grams; -coordinates: calories 3. Is there a relationship between fat and calories? Eplain. Yes; a positive relationship Answers Glencoe/McGraw-Hill A17 Glencoe Pre-Algebra
Answers () NAME DATE PERID R eading to Learn Mathematics Pre-Activit How can scatter plots help spot trends? Do the activit at the top of page 40 in our tetbook. Write our answers below. a. What appears to be the trend in sales of movies on videocassette? Sample answer: Consumers are buing less movies on videocassette. b. Estimate the number of movies on videocassette sold for 2003. about 40 Reading the Lesson Write a definition and give an eample of the new vocabular term. Helping You Remember 2. Scatter plots are used to show relationships. a. For a positive relationship, as increases, increases. b. For a negative relationship, as increases, decreases. 3. The scatter plot compares the weights and heights of the plaers on a high school football team. Heights of Football Plaers 6'1" 5'11" 5'10" 5'9" 5'8" Height NAME DATE PERID Practice Determine whether a scatter plot of the data for the following might show a positive, negative, or no relationship. 1. a person s jogging speed and time spent jogging negative 2. the size of a famil and the weekl grocer bill positive 3. the size of a car and the cost no relationship 4. a person s weight and percent bod fat positive 5. time spent plaing video games and time spent on outdoor activit negative 6. Draw a scatter plot with ten ordered pairs that shows a negative relationship. See students answers. EMPLYMENT For Eercises 7 9, use the table below, which shows the median salar for women who had completed a college degree for the ears 1989 1998. 7. Make a scatter plot of the data. 56 54 52 48 46 8. Does there appear to be a relationship between ear and salar? Yes; a positive relationship is shown. 9. Based on the graph, predict what the median salar was for the ear 2000. at least $60,000 Glencoe/McGraw-Hill 33 Glencoe Pre-Algebra Vocabular Definition Eample 1. scatter plot See students work. 6'0" 5'7" 5'6" 0 160 1 200 Weight (in pounds) a. What tpe of relationship eists, if an? In general, as the heights of the plaers increase, so do the weights. The scatter plot shows b. Based on the scatter plot, predict the weight of a 59plaer who decided to join the team. approimatel 145 pounds Glencoe/McGraw-Hill 34 Glencoe Pre-Algebra Salar (in thousands) Salar in Thousands of Dollars 1989 42 19 43 1991 45 1992 46 1993 48 1994 49 1995 1996 51 1997 53 1998 57 44 42 Median Salar 1989-1998 '89 '91 '93 '95 '97 '99 Source: Time Almanac Glencoe/McGraw-Hill A18 Glencoe Pre-Algebra