To get the most accurate results, you should always test your broadband speed whilst connected directly to your broadband router using a network cable.
If you do not have a network cable, ensure that you are standing directly in front of your broadband router. This will ensure that your results are as accurate as possible and rule out any issues such as interference or wifi black spots that may be causing broadband performance issues.
Ideally, Test whilst directly connected to your router and also over your wireless connection. This will help establish if the problem is with your Internet Service Provider (ISP) internet connection speed or your internal wireless network.