A continuous random variable $$X$$ has a probability density function $$f\left( x \right) = {e^{ - x}},0 < x < \infty .$$ Then $$P\left\{ {X > 1} \right\}$$ is

Two independent random variables $$X$$ and $$Y$$ are uniformly distributed in the interval $$\left[ { - 1,1} \right].$$ The probability that max $$\left[ {X,Y} \right]$$ is less than $$1/2$$ is

A screening test is carried out to detect a certain disease. It is found that $$12$$% of the positive reports and $$15$$% of the negative reports are incorrect. Assuming that the probability of a person getting positive reports is $$0.01,$$ the probability that a person tested gets an incorrect reports is

A random variable is uniformly distributed over the interval $$2$$ to $$10.$$ Its variance will be