13.1 A/B testing. A/B testing, or split testing, is often used to understand user behavior related to online features. It involves randomly assigning users to two levels of a single factor and comparing some outcome. Suppose a company is interested in updating its website and is considering between two background colors and between two font sizes. If using A/B testing, the company would perform two single-factor analyses: one for background color and one for font size. Write a short paragraph to the company, summarizing the benefits of considering a two-factor design in this setting.