Google put a penalty on many websites that offer poor experience to mobile users. Later on, it was confirmed that Google mobile friendly website. A Mobile Friendly Website means user can view your website easier in full layout as in desktop. You can check your website is mobile friendly or not by using Online Mobile Friendly Test tool.
List of Online Mobile Friendly Test Tool
The average of a website speed in Mobile is 50 and Desktop is 70 in (100). You can check your website speed score by using Pingdom Tools and GTmetrix. Website Making mobile friendly is also play vital roll to increase website traffic. Hope the above information will help you to optimize your website speed in mobile.