The notification arrows indicate a change from the previous result according to the following:
Recorded value is higher = upwards arrow
Recorded value is the same = horizontal arrow
Recorded value is lower = downwards arrow
Test result indicates better service = green arrow
Test result indicates worse service = red arrow
Therefore a higher latency than the previous test will be indicated by an upwards red arrow.
A higher download speed than the previous test will be indicated by an upwards green arrow.