Correlation Coefficient

r=-0.89

• Strong positive 

• Weak positive 

• Strong negative 

• Weak negative 

The scatter plot shows the number coffee shops in different cities and the number of violent crimes. Which of the following is NOT true?

• A) As the number of coffee shops increase, violent crimes appears to increase.

• B) The line of best fit (regression line) shows a positive correlation

• C) The data has a positive correlation coefficient

• D) An increase in coffee shops causes an increase in violent crimes

Estimate the correlation coefficient

• r = 1

• r = -1

• r ≈ -0.8

• r ≈ 0.8

• r ≈ -0.5

Describe a correlation with a coefficient of r=-0.89

• Strong positive

• Weak positive

• Strong negative

• Weak negative

Describe a correlation with a coefficient of r=0.3

• Strong positive

• Weak positive

• Strong negative

• Weak negative

A perfect negative correlation has a correlation coefficient of ____. 

• 1

• -1

• 0

Which graph represents data that has a correlation coefficient close to -1?

• 
• 
• 
• 

If r=0 , then there is...

• Negative association

• No correlation

• Positive association

What type of association does this graph have?

• positive

• negative

• none

• all of the above

Estimate the correlation coefficient for this scatterplot.

• r = 1.2

• r = 0.89

• r = 0

• r = -0.89