For Windows 10 users
Start Menu > Settings > Devices > Mouse and Touchpad - scroll to bottom > Additional Mouse Options
Hardware "HID Compliant Mouse" > properties > change settings
I have this (Windows Driver) disabled. From the downloads page for the drivers for Inspiron 7548 you'll get the dell updates software or proprietary driver itself but its called ETDWareUsb********.
The thing is that both drivers are trying to handle the same device at the same time.
I think the Windows 10 trackpad driver works fine but you should only have one or the other.
Having now used the latter its much more accurate and makes this trackpad turn from nightmare into something nice.
Thanks for posting and letting everyone know what you found! This is great and others having the same problem will be able to fix their computers with this method.