Chapter 2-4

What is a scatterplot and how does it help​ us? a) A scatterplot is a graph of paired​ (x, y) quantitative data. It provides a visual image of the data plotted as​ points, which helps show any patterns in the data. b) A scatterplot is a table of paired​ (x, y) quantitative data sorted from least to​ greatest, which helps show the range of the data. c) A scatterplot is a graph of paired​ (x, y) qualitative data. It provides an organized display of the​ data, which helps show patterns in the data. d) A scatterplot is a formula that fits a straight line to data​ points, which helps plot the data.

a) A scatterplot is a graph of paired​ (x, y) quantitative data. It provides a visual image of the data plotted as​ points, which helps show any patterns in the data.

If we find that there is a linear correlation between the concentration of carbon dioxide in our atmosphere and the global​ temperature, does that indicate that changes in the concentration of carbon dioxide cause changes in the global​ temperature? a) No. The presence of a linear correlation between two variables does not imply that one of the variables is the cause of the other variable. b) Yes. The presence of a linear correlation between two variables implies that one of the variables is the cause of the other variable.

a) No. The presence of a linear correlation between two variables does not imply that one of the variables is the cause of the other variable.

The table lists weights​ (pounds) and highway mileage amounts​ (mpg) for seven automobiles. Use the sample data to construct a scatterplot. Use the first variable for the​ x-axis. Based on the​ scatterplot, what do you conclude about a linear​ correlation? Weight Highway 2725 34 3355 31 3550 29 3970 25 4335 23 2145 39 3480 30 a) Yes, as the weight increases the highway mileage decreases. b) Yes, as the weight increases the highway mileage increases. c) No, there appears to be no relationship. d) No, there appears to be a​ relationship, but it is not linear.

a) Yes, as the weight increases the highway mileage decreases.

In this section we use r to denote the value of the linear correlation coefficient. Why do we refer to this correlation coefficient as being​ linear? a) The term linear refers to a straight line that passes through the average values of the paired​ data, and r measures how well a scatterplot fits a​ straight-line pattern. b) The term linear refers to a straight​ line, and r measures how well a scatterplot fits a​ straight-line pattern. c) The term linear refers to a straight​ line, and r measures the fraction of the points the best line passes through. d) The term linear refers to the straight line that passes through the greatest number of​ points, and r measures the fraction of the points the line passes through.

b) The term linear refers to a straight​ line, and r measures how well a scatterplot fits a​ straight-line pattern.

Construct a scatter diagram using the data table to the right. This data is from a study comparing the amount of tar and carbon monoxide​ (CO) in cigarettes. Use tar for the horizontal scale and use carbon monoxide​ (CO) for the vertical scale. Determine whether there appears to be a relationship between cigarette tar and CO. Tar Co 16 15 16 16 1 1 17 18 5 7 14 13 8 11 10 10 18 18 9 11 2 3 11 12 6 7 11 10 15 15 a) No, there appears to be no relationship. b) ​Yes, as the amount of tar increases the amount of carbon monoxide also increases. c) Yes, as the amount of tar increases the amount of carbon monoxide decreases.

b) ​Yes, as the amount of tar increases the amount of carbon monoxide also increases.

The table provided below shows paired data for the heights of a certain​ country's presidents and their main opponents in the election campaign. Construct a scatterplot. Does there appear to be a​ correlation? Pres. Height Opp. Height 181 187 180 193 177 170 192 177 184 171 196 178 175 180 176 192 169 168 195 184 187 177 184 174 180 176 196 190 184 189 170 177 a) Yes, there appears to be a correlation. As the​ president's height​ increases, his​ opponent's height increases. b) Yes, there appears to be a correlation. The candidate with the highest height usually wins c) Yes, there appears to be a correlation. As the​ president's height​ increases, his​ opponent's height decreases. d) Yes, there appears to be a correlation. As the​ president's height​ increases, his​ opponent's height decreases.

d) Yes, there appears to be a correlation. As the​ president's height​ increases, his​ opponent's height decreases.