Auto Batteries. In October 2002, Consumer Reports listed the price (in dollars) and power (in cold cranking amps) of auto batteries. We want to know if more expen- sive batteries are generally better in terms of starting power. Here are the regression and residual output, where the response variable is Power.
Dependent variable is: Power R squared = 25.2% s = 116.0 with 33 - 2 = 31 degrees of freedom
Variable Coefficient SE(Coeff) t-ratio P-value
a) Is there evidence of a linear association between the price and cranking power of auto batteries? Test an appro- priate hypothesis and state your conclusion.
b) Is the association strong? Explain.
c) What is the equation of the regression line?
d) Create a 90% confidence interval for the slope of the true line.
e) Interpret your interval in this context.