Simple Probability Question
I took a quiz for my probability question, and apparently I answered this question wrong, but I don't know where I went wrong?
Here is the question:
A computer program is tested by 3 independent tests. When there is an error, these tests will discover it with probabilities 0.2, 0.3, and 0.5, respectively. Suppose that the program contains an error. What is the probability that it will be found by at least one test?
Here is my work:
P(at least one test with error) = 1 - p(no errors detected)
= 1 - (1-0.2)(1-0.3)(1-0.5)
= 1 - 0.8 * 0.7 *0.5
Does anyone know where I went wrong, or possibly confirm that I got this right and the computer got it wrong?