Attached is a dataset.

The research question is;

How does engine size affect city mpg?

_{(the answer is the larger the engine the lower the mpg - inversely proportional)}

Both the variables engine size and city mpg are NOT normally distributed. They are also both continuous. Therefore a non-parametric test should be used. Which test is suitable in this case and why?

Model Eng Highway Size Cylinders - MSRP City Mpg Mpg Weight - Type Country 3_Series 2.5 6 28100 20 29 3219 Sedan Germany 5_Series 2.5 6 39800 19 28 3428 Sedan Germany 7451 4.4 8 69300 18 26 4376 Sedan Germany 9-5_Aero 2.3 4 39860 19 28 3470 Sedan Sweden A4 1.8 4 25550 22 31 3252 Sedan Germany A6 2.7 6 42650 18 25 3836 Sedan Germany A8_L 4.2 8 68500 17 24 4399 Sedan Germany Accord_LX 2.4 4 20100 24 33 3164 Sedan Japan Aerio 2.3 4 15199 25 31 2676 Sedan Japan Altima 2.5 4 19200 23 29 3088 Sedan Japan Astro_LS 4.3 6 25230 16 20 4309 Minivan US Avalon_XL 3 6 26965 21 29 3428 Sedan Japan Bravada 4.2 6 35870 15 21 4600 SUV US C-class 1.8 4 29250 22 30 3250 Sedan Germany