Correlation and R Value Review

Estimate the correlation coefficient for this scatterplot.

• r = 0.56

• r = -0.56

• r = 0.92

• r = -0.92

Which of the following statements is not true of the correlation r between the lengths in inches and weights in pounds of a sample of brook trout?

• r must take a value between -1 and 1.

• r is measured in inches.

• If longer trout tend to also be heavier, then r>0.

• r would not change if we measured the lengths of the trout in centimeters instead of inches.

Describe the correlation in the graph shown.

• Strong Negative

• Strong Positive

• Weak Negative

• Weak Positive

The correlation coefficient measures...

• whether there is a relationship between two variables.

• the strength of the relationship between two quantitative variables.

• whether a cause and effect relation exists between two variables.

• the strength of the linear relationship between two quantitative variables.

What is the correlation coefficient of the regression line?

• 0.986

• 2527

• total length (cm) = 1.1forklength (cm) + 4.1

• 4.1

Determine the correlation coefficient of the given data.

• - .5477

• .1770

• .8956

• - .9463

What is the formula for calculating correlation coefficient?

• (nΣxy + ΣxΣy) / √((nΣx^2 + (Σx)^2)(nΣy^2 + (Σy)^2))

• (nΣxy - ΣxΣy) / ((nΣx^2 - (Σx)^2)(nΣy^2 - (Σy)^2))

• (nΣxy - ΣxΣy) / √((nΣx^2 - (Σx)^2)(nΣy^2 - (Σy)^2))

• (nΣxy - ΣxΣy) / ((nΣx^2 - (Σx)^2) + (nΣy^2 - (Σy)^2))

Choose two words from those listed below to best describe the correlation between the two variables.

• strong

• weak

• positive

• negative

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

• -0.999

• -0.664

• 0.998

• 1.503

Which of the following statements are supported by the scatterplot?
I.  There is a positive association between height and volume.
II.  There is an outlier in the plot. 
III.As the height of a cherry tree increases, the volume of useable lumber it yields increases.

• I only

• II only

• I and II only

• I, II, and III