The correlation of crank arm length to height isn't rocket science. There are those who believe that taller people should have longer cranks, but it doesn't always hold true. Shorter people often need shorter arms to, but taller people who can use longer arms don't always benefit. Probably (opinion) what's more important is pedaling style and cadence. Spinners tend to like shorter arms, and tall mashers prefer the added leverage of longer ones. Even the leverage issue has to be considered in view that the gearing controls leverage too -- want more leverage, ride a lower gear.