2.6 Quick Check

Seven married couples were interviewed about their height difference. Describe the correlation between the height of partner 1 compared to the height of partner 2.

• The correlation coefficient is less than 0.5 meaning there is a weak correlation between the heights of married couples.

• The correlation coefficient is between 0.5 and 0.75 meaning there is a moderate correlation between the heights of married couples.

• The correlation coefficient is more than 0.75 meaning there is a strong correlation between the heights of married couples.

Calculate the regression line for the data set.

Ten soccer teams were asked about the total number of goals they have scored so far this season and their number of wins so far this season. The data is presented in the table. Calculate the correlation coefficient for the data.

• 0.715

• 0.591

• -0.409

• 0.845

Ten soccer teams were asked about the total number of goals they have scored so far this season and their number of wins so far this season. The data is presented in the table. Write the regression line for the data.

The graph represents the weight (in lbs) and fuel efficiency (in miles per gallon) for seventeen 2014 sedans. The outlier in the lower right represents the 2014 Bentley Mulsanne (which costs $305,325 and whoever buys it probably does not care about fuel efficiency). Describe how the outlier affects the correlation.

• The outlier is making the correlation stronger.

• The outlier is making the correlation weaker.

Which regression line below best represents the graph pictured?

Answer explanation

Slope is negative and the y-intercept is in between 40 and 42 on the graph

The graph shows the data for 8 tuna that were caught and sold during a fishing competition. There are 3 major outliers on this graph marked in red. The red line shows the regression line if the outliers are included. The green line shows the regression line when the outliers are removed.

Describe how the outliers affect the regression line when included.

• The regression line has a steeper slope and a negative y-intercept.

• The regression line has a slope that is less steep and a positive y-intercept.

• The regression line has a steeper slope and a positive y-intercept.

• The regression line is not affected by outliers.

The graph shows 10 tuna that were caught and sold. Which correlation coefficient accurately reflects the correlation between the weight of the tuna and the price it sold for?

• 0.75

• 0.96

• -0.98

• 0.98

Calculate the regression line for the data.

• $26 million

• $0.2 million

• $263,000

• $263 million