I have issues understanding probability.
I have this problem:
A device for checking welds in pumps is designed to signal if the weld is defective. If the weld is actually defective, the probability the device will give a signal is .94.
If the weld is actually not defective, the probability the device will give a signal is .05.
It is known that 3% of welds on pumps are defective. A weld is selected at random and checked by the device.
1- What is the probability the device will be correct?
2- Suppose the device gives a signal for the checked weld. What is the probability the weld is actually not defective (false positive)?
For the first question,
I did this:
The second I dont know what to do.
Please can someone help me ?