The following measurements were gathered for 16 popular sports and GT cars: price (in thousands of dollars), curb weight, horsepower, and "speed at 1/4 mile" (the maximum speed attained after 1/4 mile from a standstill). A regression analysis was performed to estimate 1/4 mile speed using price, curb weight and horsepower.

1) What portion of the total variation in "speed at 1/4 mile" is explained by price (in thousands of dollars), curb weight and horsepower?

2) In testing the coefficient for horsepower to see if the variable horsepower has any explanatory power in our model, the calculated test statistic is

Not sure of how to even this. Can anyone lend a hand and show some work and how to get an answer.

Thanks