Mason and Ethan are using their computers to take part in an online experiment on a website. When Mason presses the space bar on his keyboard, there is a 50% probability that his screen turns blue. When Ethan presses the space bar on his keyboard , there is a 45% probability that his screen turns blue. If they both press their space bars, there is a 15% chance that both of their screens turn blue. Are "Mason's screen turning blue" and "Ethan's screen turning blue" independent events ?