Data606 Presentation

J Mehta
May 9, 2017

Question 7.30 (Intro To Linear Regression)

(a) Write out the linear model.

h = -0.357 + 4.034b

where h is cat's heart weight, and b is cat's body weight

(b) Interpret the intercept.

The intercept is -0.357

If we set the value of cat's body weight as 0, then its heart weight would -0.357 grams. This points to the fact that is simply an adjustment factor.

(c) Interpret the slope.

The slope is 4.034

This implies a positive correlation between the body weight and heart weight. For every 1 kg increase in cat's body weight, its heart weight goes up by nearly 4 grams.

(d) Interpret R-square.

R squared is 64.66%

This implies that the Regression line explains ~65% of the variation in cat's heart weight when measured against its body weight.

(e) Calculate the correlation coefficient.

Correlation = SQRT(R-Squared)

sqrt(0.6466)

[1] 0.8041144