Correlation

Correlation Coefficient

The closer to 0, the weaker the correlation. Very close to 0 is no correlation. The closer to -1 or 1, the stronger the correlation. -1 and 1 are perfect.

Multiple Choice

Estimate the correlation coefficient for this scatterplot.

• r = 1.2
• r = 0.89
• r = 0
• r = -0.89

Multiple Choice

Estimate the correlation coefficient for this scatterplot.

• A) r = -0.9

• B) r = 1

• C) r = 0.9

• D) r = -1

Multiple Choice

A perfect positive correlation has a correlation coefficient of ____. 

• 1
• -1
• 0

Multiple Choice

A perfect negative correlation has a correlation coefficient of ____. 

• 1
• -1
• 0

Multiple Choice

What type of association does this graph have?

• positive
• negative
• none
• all of the above

Multiple Choice

What type of correlation does this scatter plot show?

• Positive correlation

• Negative correlation

• No correlation

• Constant correlation

Multiple Choice

Which graph depicts the strongest positive correlation?

Multiple Choice

• Positive, strong
• Positive, weak
• Negative, strong
• Negative weak

Multiple Choice

r=-0.89

• Strong positive 
• Weak positive 
• Strong negative 
• Weak negative 

Multiple Choice

Is this line an accurate line estimate of best fit for the data?

• Yes

• No

Correlation Coefficient and Equation of Line

​DESMOS: y₁ ~ mx₁ + b

​"r" = correlation coefficient
- above 0.5 strong, below 0.5 weak
- is "m" positive or negative

Multiple Choice

Using your DESMOS determine the line of best fit and the correlation coefficient of the data in the table.

• y = 4.6x - 347

  r = .942

• y = 4.6x - 347

  r = .888

• y = 4.6x + 347

  r = .942

• y = 4.6x + 347

  r = .888

Multiple Choice

As shown in the table, a person's target heart rate during exercise changes as the person gets older. Use DESMOS to find the correlation coefficient (r).

• -0.999

• -0.664

• 0.998

• 1.503

Multiple Choice

What is the line of best fit?

• f(x)= 5x+1.82
• cannot be determined
• f(x)= 1.82x + 5.02
• f(x)= 1.1x + 4.2