Researchers studied a way to measure the octane number of gasoline using a method called proton magnetic resonance (PMR) spectrometry. They analyzed samples of winter gasoline and high-olefin gasoline to improve the accuracy of estimating octane numbers. By comparing PMR data with known octane numbers, they created a linear equation to estimate octane numbers more accurately. This method was found to be useful for estimating octane numbers of different types of gasoline.