Consumer Reports listed the price (in dollars) and power (in cold cranking amps) of auto batteries. We want to know if more expensive batteries are generally better in terms of starting power. Here are the regression and residual output, where the response variable is Power.

a) How many batteries were tested?
b) Are the conditions for inference satisfied? Explain.
c) Is there evidence of a linear association between the price and cranking power of auto batteries? Test an appropriate hypothesis and state your conclusion.
d) Is the association strong? Explain.
e) What is the equation of the regression line?
f) Create a 90% confidence interval for the slope of the true line.

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Dependent variable s: Power R-squared 25.2% s116.0 with 33 231 degrees of freedom Variable Coefficient SE(Coeff) t-Ratio P-Value 93.55 Intercept Price 384.594 4.146 4. 0.000 3.23 0.0029 1.282 800 700 600 500 50 75 100 Price (S) 200 100T -100 600 700 800 Predicted (cold cranking amps) 200 100 -100 0.00 1.25 Normal Scores